vol. 49 no. 4 fall 2015 colorado birds vol 49/cb_2015_49_4_fall.pdf166 colorado birds fall 2015 vol....

Vol. 49 No. 4 Fall 2015

The Colorado Field Ornithologists’ Quarterly

Colorado Birds

Colorado's Breeding Bird Atlas IIGrand Valley CBC—99 Western Screech-OwlsThe Hungry Bird—A Shrike Stash

166 Colorado Birds Fall 2015 Vol. 49 No. 4

Colorado Field OrnithologistsPO Box 929, Indian Hills, Colorado 80454

cfobirds.org

Colorado Birds (USPS 0446-190) (ISSN 1094-0030) is published quarterly by the Col-orado Field Ornithologists, P.O. Box 929, Indian Hills, CO 80454. Subscriptions are obtained through annual membership dues. Nonprofit postage paid at Louisville, CO. POSTMASTER: Send address changes to Colorado Birds, P.O. Box 929, Indian Hills, CO 80454.

Officers and Directors of Colorado Field Ornithologists: Dates indicate end of cur-rent term. An asterisk indicates eligibility for re-election. Terms expire at the annual convention.

Officers: President: Doug Faulkner, Arvada, 2017*, [email protected]; Vice Presi-dent: David Gillilan, Littleton, 2017*, [email protected]; Secretary: Larry Modesitt, Greenwood Village, 2016, [email protected]; Treasurer: Michael Kiessig, Indian Hills, 2017*, [email protected]

Past President: Bill Kaempfer, Boulder, 2016, [email protected]

Directors: Christy Carello, Golden, 2016*; Lisa Edwards, Palmer Lake, 2017; Ted Floyd, Lafayette, 2017; Mike Henwood, Grand Junction, 2015*; Christian Nunes, Longmont, 2016*; Chris Owens, Denver, 2018*

Colorado Bird Records Committee: Dates indicate end of current term. An asterisk indicates eligibility to serve another term. Terms expire 12/31.

Chair: Mark Peterson, Colorado Springs, 2018*, [email protected]

Committee Members: John Drummond, Colorado Springs, 2016; Peter Gent, Boulder, 2017*; Tony Leukering, Largo, Florida, 2015*; Dan Maynard, xxx, 2017*; Bill Schmok-er, Longmont, 2016; Glenn Walbek, Castle Rock, 2015

Past Committee Member: Bill Maynard

Colorado Birds Quarterly:

Editor: Peter Burke, [email protected]

Staff: Christy Carello, science editor, [email protected]; Christian Nunes, photo editor, [email protected]

Contributors: David Dowell, Dave Leatherman, Tony Leukering, Bill Schmoker

Annual Membership Dues (renewable quarterly): General $25; Youth (under 18) $12; Institution $30. Membership dues entitle members to a subscription to Colorado Birds, which is published quarterly. Back issues/extra copies may be ordered for $7.50. Send requests for extra copies/back issues, change of address and membership renewals to [email protected]. Contributions are tax deductible to the extent allowed by law.

COPYRIGHT © 2015 by Colorado Field Ornithologists. Reproduction of articles is permitted only under consent from the publisher. Works by U.S. and Canadian governments are not copyrighted.

The Colorado Field Ornithologists’ Quarterly Vol. 49 No. 4 Fall 2015

PRESIDENT’S MESSAGE ....................................... 168Doug Faulkner

ABOUT THE AUTHORS ......................................... 170

CFO BOARD MEETING MINUTES ......................... 172Larry Modesitt

CFO TRIP REPORT ................................................ 174 Mike Henwood

ALEXANDER WILSON .......................................... 176Robert Righter

COLOROAD'S BREEDING BIRD ATLAS II ............. 180Lynn Wickersham

VAUX'S SWIFT: COLORADO'S 499TH SPECIES..... 183Brandon Percival

FULLY EXPOSED .................................................. 185Bill Schmoker

GRAND VALLEY CBC 2014 ................................... 189Nic Korte

CFO CONVENTION PAPERS .................................. 197Christy Carello

NEWS FROM THE FIELD: SPRING 2015 .............. 205David Dowell

72ND REPORT OF THE CBRC ............................... 221Mark Peterson, Bill Maynard

COMPUTER MODELING TO IMPROVEFLOCK-SIZE ESTIMATES ...................................... 239Alyssa H. Rawinski

THE HUNGRY BIRD ............................................. 247Dave Leatherman

IN THE SCOPE ...................................................... 255Tony Leukering

Eastern Screech-Owl, Poudre River, Larimer Coun-ty, 9 May 2013. Photo by Dave Leatherman


CFO Provides Toolsfor Colorado BirdersDoug Faulkner

What do Short-eared Owl, Red-hooded Tanager, and Pale-naped Brush-Finch have in common? They’re all species that occur in Azuay Province, Ecuador, and they’re all species I did not see this past year.

You see, my family and I just spent the past year living in Cuenca, Ecuador. Yes, Ecuador, the country that boasts the highest average number of species per square mile than any other in the world, roughly one species per 60 square miles, and I spent an entire 11 months primed to add a significant number of birds to my life list. Well, almost.

Cuenca is a fairly large, modern city with a metropolitan population around 400,000. The city sits at about 8,000 feet elevation in a sprawl-ing Andean valley. Like any city of that size it is more concrete jungle than it is Amazonian rain-forest. The species list is paltry with perhaps 20 or so regular species to be found year-round. At

least, that’s what it felt like from my experience. So, to do any serious birding I had to leave the city and that’s where I hit a snag.

While living in a country the size of Colorado, but boasting around 1,660 species might sound ideal, I found it challenging to go it alone. The birding resources available are limited. Foreign birders rarely have the information they need to travel and bird with confi-dence by themselves – after all, that’s one reason why the bird guid-ing business is so robust. Sure, I could read about habitat preferences and elevational range limits for a particular species in a field guide or online, but those resources rarely give directions, helpful hints or much narrative describing anything useful to find the species by one-self. Without much for guidance, when I boarded that plane heading back to the States I did so knowing that, to paraphrase a popular gambling saying, I had “left birds on the table.”

Now that I’m back in Colorado, I am delighted to have a readily available tool for birding the entire state – CFO’s County Birding website. If you haven’t taken the opportunity to peruse what it has to offer, I encourage you to put down this journal and get online immediately! Conveniently found under the Birding Resources tab

PRESIDENT’S MESSAGE

Doug Faulkner

Colorado Birds Fall 2015 Vol. 49 No. 4 169

on the CFO website (www.cobirds.org) or on its own (www.colora-docountybirding.org), this site has everything I wish I’d had in Ecua-dor. In addition to providing species lists for each county, it also has pertinent and useful information about the best birding spots includ-ing directions, specific areas to search for target species and available amenities (restrooms, anyone?). And with BirdTrax from eBird, you can learn what other birders have found at that location to help you further prepare.

I won’t try to convince you that this past year was anything but wonderful. It’s no secret that Ecuador is a spectacular country with huge birding potential. Going it alone, though, has its challenges. So while Colorado averages just one species per 208 square miles, with the Colorado County Birding website at hand, I’m confident that I won’t be leaving birds on the table.

Snow and Ross’s Geese, North Sterling Reservoir, Logan County, 8 March 2015. Photo by David Dowell


ABOUT THE AUTHORS

Contributors

News From the FieldDavid Dowell is an outdoor enthusiast based in Longmont. When he isn’t hiking or birding, he’s working as a meteorologist at the NOAA Earth System Research Laboratory in Boulder, trying to make thunderstorm forecasts better.

The Hungry BirdDave Leatherman is a photographer, entomologist and expert on Colorado birds. He is a regular contributor to Colorado Birds as author of The Hungry Bird. His photographs of birds carry-ing food are of such high quality that many of the invertebrates can be identified to species. He obtained his B.S. from Marietta College and his M.S. from Duke University. When not birding, Dave has been known to occasionally enjoy a night on the town listening to live jazz.

In The ScopeTony Leukering is a freelance ornithologist currently based in Florida. His primary interest in birds is migration, and his work has included nearly 14 years at the Rocky Mountain Bird Ob-servatory. He is a recipient of CFO’s Ron Ryder Award and has authored virtually all of the In The Scope columns for Colorado Birds.

Fully ExposedBill Schmoker is a middle school science teacher, is extremely active in the birding community and is a frequent photo con-tributor to Birding and other ABA publications in addition to a wide variety of books, magazines and other media. He authored the Geared for Birding column in the American Birding Asso-ciation’s Winging It newsletter and contributes to birding blogs for both ABA and Leica. He is involved with the ABA Young Birders program as a Camp Colorado and Camp Avocet instruc-tor and photo module judge for the Young Birder of the Year contest. Bill is an eBird reviewer and member of the Colorado Bird Records Committee and is a past president of CFO.


Featured Authors

Alexander WilsonRobert Righter is co-author of Colorado Birds, Birds of Western Colorado and author of Bird Songs of Rocky Mountain States. He has lived in Colorado for 47 years, 34 of them as a CFO member.

Colorado’s Second Breeding Bird AtlasLynn Wickersham has worked as an avian ecologist for nearly 20 years, with a focus on reproductive ecology of Neotropical migratory birds. In addition to serving as senior avian ecologist with Animas Biological Studies in Durango, she’s also the State-wide project manager for the Second Colorado Breeding Bird Atlas. She developed a love of nature and birds as an under-graduate at Colorado State University, and has been fortunate to have studied and worked on a variety of bird research projects across the continental U.S. After the The Second Breeding Bird Atlas is published, Lynn has plans to take some much need rest and relaxation and go skiing and birding.

2014 Grand Valley Christmas Count: 99 Western Screech-OwlsNic Korte is a geochemist specializing in groundwater contami-nation issues. He is a former president of Grand Valley Audubon and has been the conservation chairman since the early 1990s. His blog Birds and More can be read at the Grand Junction Daily Sentinel’s webpage: www.gjsentinal.com/blogs_and_more

Computer Modeling to Improve Flock-size EstimatesAlyssa H. Rawinski is a freshman at Monte Vista High School in Monte Vista, Colorado. Her paper summarizes her 2015 sci-ence fair project titled, Do Certain Traits, Skills or Characteristics Affect Bird Estimating Accuracy, and Can a Computer Model Im-prove Estimating Accuracy? You Can Count on It! She took first place in her division of the San Luis Valley Regional Science Fair and was awarded Best Project for Monte Vista Middle School. She competed in the State Science Fair in Fort Collins, Colo-rado, in 2015 and was invited to the 2015 Intel Science and Engi-neering Fair held in Pittsburgh, Pennsylvania in May 2015 as an observer. Alyssa plays piano and flute and enjoys hiking, camp-ing and crafts and is especially fond of rock hounding: searching for crystals, geodes, mossy agate, petrified wood and fossils.


CFO BOARD MEETING MINUTES

12 September 2015 Bird Conservancy of the Rockies Headquarters, Barr Lake State Park, Brighton, CO

Larry Modesitt

President Doug Faulkner called the September quarterly meet-ing to order at 11:08 a.m. The board welcomed new board members Michael Kiessig and Chris Owens, and the return of board member Mark Peterson. Other officers present were Vice President David Gil-lilan and Secretary Larry Modesitt. Directors Peter Burke, Christy Carello, Bill Kaempfer and Christian Nunes were present. Directors Lisa Edwards, Ted Floyd and Mike Henwood sent their regrets.

Secretary’s Report: Larry Mode-sitt’s minutes of the 18 April 2015 board meeting were approved.

Treasurer’s Report: Michael Kies-sig’s previously emailed financial state-ments for the second quarter of 2015 were approved. Directors reviewed the application for a Treasurer’s bond for $50,000 of insurance and believed that the $99 premium, while inexpen-sive, appeared to exclude the events for which we would want insurance. Michael will investigate further.

Items of Business from the Presi-

dent1. Cobirds Moderator Position.

Todd Deininger has requested to be relieved from the position of mod-erator and Lisa Edwards is seeking a replacement. The job of the modera-tor is to approve new members’ initial posts and moderate COBirds content.

2. Lynn Wickersham has requested additional funding for the second Col-orado Breeding Bird Atlas (CO BBA II). The board discussed the request and asked Doug Faulkner to inves-

tigate the financial projections with Lynn. If action is to be taken, Doug will poll the board by email.

Project Fund and Scholarships—Christy Carello asked last year’s re-viewers Catherine Ortega and Na-than Pieplow for feedback regarding the process of approving funding. We agreed to add the following requests: a recommendation from the requestor’s organization, return of the funding if the project is not done and informa-tion regarding previous CFO funding. We agreed that equipment of general use beyond project use will not be funded, but funds for field assistants, which many grantors do not fund, may be approved.

CFO-Western Field Ornithologists (WFO) Partnership—Larry Modes-itt reported that WFO, in partnership with CFO, is beginning to plan for a fall convention in 2017. CFO mem-bers thus will be able to attend both fall and spring conventions that year. We suggested that WFO be responsible for selecting convention location and


timing, recruiting speakers, determin-ing food & banquet arrangements and handling registration. CFO’s would help recruit trip leaders. Certain au-thors of articles in Western Birds have requested insertion of Digital Object Identifiers. The purpose of the DOI is to make articles more easily searchable and to raise the profile of both authors and the magazine. We will investigate applicability for Colorado Birds.

Bylaws Overview—David Gilli-lan suggested a review of bylaws to see if some aspects are obsolete or could become clearer. We agreed to form an ad hoc committee, with David as chair, and with Bill Kaempfer, Doug Faulkner and Larry Modesitt as addi-tional members.

Colorado Bird Records Commit-tee (CBRC)—Mark Peterson has begun as chairman, replacing Doug Faulkner, who left to become Chair-man of CFO. Dan Maynard becomes the newest committee member.

CFO Website—David Gillilan re-ported strong usage for our three web-sites. An average of 137 people access the CFO website (cobirds.org) daily. We discussed the information on the website, and how to make it better. He suggested adding field reports and board meeting minutes on our website. For our online convention brochure, David suggested adding an information page on our website for people to read before entering the registration process.

Social Media Communications—Christian Nunes reported 1,265 Face-

book followers, up 210, or nearly 20 percent in just three months.

Additional Committee Reports 1. Colorado Birds—Peter Burke

reported that a number of science articles will be in the next issue. He suggested an article, “Where are they now?” for past birding spots that no longer are great, such as Bonny Reser-voir.

2. Publicity—Ted Floyd reported that the 2015 Convention report, bird list and photos are now online.

3. Membership—Lisa Edwards re-ported that Colorado Birds circulation is now 568 issues, 43 higher than the same time last year.

4. Nominations & Awards—Doug Faulkner appointed Chris Owens to succeed Joe Roller as Committee Chair, with Larry Modesitt and Joe Roller agreeing to remain commit-tee members. The only term-limited member of the board is Larry Modesitt. We agreed it is important to get more committee participation as a means of meeting new people.

5. CFO Field Trips—Mike Hen-wood’s trip to the Grand Plateau was successful, missing only Northern Goshawk of eight target birds. Bill Kaempfer discussed the Riverside Reservoir field trip. Since attendance was not limited, twenty-five people braved the brisk northwest wind; none, fortunately, were blown to Kansas. Bill also mentioned his two-day northeast Colorado trip, limited to three carloads, which was instead buffeted by a south wind. Notable birds were a Red-shouldered Hawk and a Sabine’s Gull. The next three-


car CFO trip will be October 10-11, with Bill Kaempfer and Ted Floyd, beginning at Fox Ranch and target-ing a difficult to see bird, Sprague’s Pipit. On Sunday, the group will be blown by choice to Rock Creek in Nebraska.

2016 Lamar Convention Plan-ning—Doug Faulkner

1. Facilities. CFO’s 2016 conven-tion will be May 5–9, 2016 in Lamar. Doug will scout Lamar next week to determine proposed facilities for the picnic and the motel, and assistance

from both the Lamar Chamber of Commerce and local birders.

2. Ask Me. Chris Owens requested and received feedback from conven-tion attendees, and she announced several improvements.

The next meeting will be at 11:00 a.m. on November 7, 2015 in Lamar.

President Faulkner adjourned the meeting at 4:30 p.m.

Respectfully submitted, Larry Modesitt, Secretary

CFO TRIP REPORT

June Uncompahgre Plateau TripsMike Henwood

June 12–14 Weekend TripA group of seven hardy CFO birders met on Thursday, June 12, at

the Columbine Campground near Columbine Pass on the Uncom-pahgre Plateau to spend a weekend birding. We were able to find all our target species (except for Northern Goshawk) during the weekend of birding, and were spared the heavy rains from earlier in the week.

Owling on Friday night produced a calling Flammulated Owl plus a Great Horned Owl and another Flam calling during the night at the campground. Three of us went out owling again Saturday night and heard two Flammulated Owls calling plus a Northern Saw-whet Owl doing it’s “saw-whet” call at close range. Two of the folks who stayed at the campground Saturday night witnessed a comedy show featur-ing a young Great Horned Owl that flew toward them and awkwardly attempted to land on a branch, then slipped and did a somersault be-fore righting itself and flying to another branch. Earlier on Saturday evening we watched three Common Nighthawks cruise through the campground at ground level, putting on quite a show as they coursed just above the ground, weaving expertly through the campsites.


Our five-mile hike on Saturday morning got off to a good start with a sing-ing Fox Sparrow and Orange-crowned Warbler in a willow carr. We left the Divide Road at FS Trail 412 and hiked to Beef Pasture Point and back through a variety of different habitats. Some of the highlights along the way included flushing two male Dusky Grouse, listening to singing Lincoln Sparrows, observ-ing a singing Golden-crowned Kinglet close-up and a brief look at a bear. Ar-riving at Beef Pasture Point, we observed Purple Martins entering and leaving a nest cavity in an aspen. We ate lunch in the area watching Purple Martins and Violet-Green Swallows soaring above us in the open meadow adjacent to the aspen forest. A pair of Red-naped Sapsuckers was delivering food to a cavity in an aspen while a herd of 60-70 elk with calves lounged around a beaver pond. The return trip produced another Dusky Grouse that exploded underfoot to reveal a nest with 8 eggs. A pair of Gray Jays was a pleasant surprise just before returning to the Divide Road. We spent the rest of the afternoon birding our way back to Columbine Campground, making short detours along the way. A highlight was finding a female Three-toed Woodpecker, as well as more Red-naped and Williamson’s Sapsuckers entering nesting cavities.

Sunday morning the group drove to the Tabeguache Basin area where we heard Grace’s Warblers. Our patience finally paid off with some good looks at a pair of Grace’s Warblers, a lifer for several folks in the group.

June 20–Driving Trip on the Divide RoadA group of five CFO members met in Grand Junction on Saturday, June 20

for a day of driving and birding along the Divide Road over the Uncompah-gre Plateau. We were able to see most of the birds seen by the weekend group the week before, missing only the Three-toed Woodpecker and with only brief looks at flying Purple Martins. At our first stop at Jack’s Canyon, we spotted a hard-to-find Hernandez’s Short-horned Lizard (horny toad). Subsequent stops at Carson’s Hole and the Telephone trail produced Red-naped and Williamson’s Sapsuckers visiting nesting cavities in aspen, as well as Mountain and Western Bluebirds, also visiting nests. We heard singing Grace’s Warblers at the Tele-phone Trail stop and were able to see singing Brewer’s and Vesper Sparrows, Green-tailed Towhees and Western Meadowlarks in the mountain parks thick with shrubs and sage. A large willow carr in a broad valley produced singing Fox Sparrows along with Yellow, Orange-crowned and MacGillivray’s Warblers. Lewis’s Woodpeckers were numerous in the area and provided great looks both perching and fly catching. Our lone Dusky Grouse was seen along the Divide Road and a pair of Sandhill Cranes was seen just before dark standing in a pond near the Escalante SWA west of the town of Delta. Everyone agreed it was a long, yet rewarding day of birding.

Mike Henwood, [email protected]


Alexander Wilson 1766–1813Bob Righter

Born in Paisley, Scotland, Alexander Wilson spent his first 20 years as a weaver, peddler and a smuggler, yet it was his poetry he was best known for. His youth was spent reading all of the great poets of the time including Milton, Burns, Pope, Bruce, Goldsmith and

Virgil. Wilson placed second at a young poet’s contest in Edinburgh. In fact, one of his poems, Watty and Meg, sold a hundred thousand copies, which at the time was considered a whopping success, and even by today’s standards would be considered a great achievement. Ultimately it was a poem that would change the course of his life. Wilson was imprisoned after publishing a satirical poem that detailed the cruel work-ing conditions for weavers in a local mill. He was required to burn the poem in public and was pressured to leave the country. Scotland’s loss was America’s gain, as Wilson would be-come the New World’s first pre-eminent orni-thologist who has been dubbed the “Father of American Ornithology.”

Wilson departed Ireland on a boat named the Swift, arriving in New Castle, Delaware, in July 1794. Without a penny in his pocket, he had no idea what to do in America. Making

his way to Philadelphia, he serendipitously came across a Red-headed Woodpecker—the most beautiful bird he had ever seen. Little did Wilson realize that he was becoming smitten with the birds of his new homeland.

Living in the New WorldWilson found employment as a teacher, and held several positions

in New Jersey and Eastern Pennsylvania before settling in the Phila-delphia suburb of Kingsessing. It was there that he met the natu-ralist John Bartram, whom Carl Linnaeus described as “the greatest botanist in the world.” Bartram had traveled the American colonies extensively and established a botanic garden in Kingsessing thought to be the first in America, which is still in existence today. John Bar-tram and his son William encouraged Wilson’s budding interest in birds. It was William who introduced Wilson to the accomplished

“Alexander Wilson, 1766–1813." Licensed under Pub-lic Domain via Commons


American painter Charles Willson Peale. As a result of Peale’s influ-ence, Wilson learned to paint birds.

Bartram and Peale were both early supporters of Linnaean tax-onomy. Wilson had a keen eye for detail, and adopted a style of paint-ing birds that often included important botanical illustrations and/or taxonomic groupings. In 1806 Meriwether Lewis, newly returned from his epic expedition with William Clark, noted of Wilson’s paint-ings, “that no one in America had painted wildlife with the precision and feeling as Wilson.”

American OrnithologyWilson had a bold vision to illustrate and publish a collection of all

the birds of North America. Consulting with a printer, he calculated what it would cost to produce a nine-volume set of books, which he would name American Ornithology. To cover his costs, he determined that he would need to sell 200 subscriptions. Wilson virtually walked his way through New England, often covering 50 miles in a day, and gathered 41 subscribers for a total of $4,920. In fact it has been esti-mated that in two years Wilson walked 10,000 miles, 1,000 of them with his pet parrot, Polly, on his shoulder. Along the way, Wilson’s stature was rising. One prominent Philadelphian described him as “one of the most remarkable people he had ever known.” Among his early subscribers was none other than Thomas Jefferson.

Wilson traveled almost constantly in search of new species of birds and new subscribers to American Ornithology. Outside Wilming-ton, North Carolina, he found a wounded Ivory-billed Woodpecker. Wilson wrapped the bird in his jacket and checked into a hotel hop-

Wilson’s Phalarope


ing he could nurse the woodpecker back to health. While he was eating dinner, the Ivory-billed Woodpecker got loose and destroyed his room. The floor was covered in plaster and there was a hole in the wall the size of a man’s fist. Splinters from a fine mahogany table were scattered everywhere.

In February 1810 Wilson headed west. At a stop in Louisville, Kentucky, he responded to an ad in a local paper offering drawing lessons. Intrigued, Wilson arrived at the store and was greeted by a gentleman who spoke with a French accent. The man was impressed with Wilson’s sketches of birds and offered to share some of his own… Thus did Alexander Wilson make the acquaintance of John James Audubon! There is no detailed account of how each felt about this chance encounter, but one can only imagine the shock they must have experienced in learning that they were each chasing the same dream. The encounter was not mentioned in Wilson’s journals and letters, and Audubon made only passing reference to the meeting some years after Wilson’s death.

Traveling through Kentucky, Ohio and Tennessee in April, right at the height of eastern warbler migration, Wilson discovered and described six new warbler species: Nashville, Magnolia, Bay-breast-ed, Cerulean, Kentucky and Bay-breasted. In Shelbyville, Kentucky, Wilson observed a flight of Passenger Pigeons that he estimated at 200 million, stretching for 240 miles. He eventually reached Mis-sissippi, then the western US boundary as the Spanish owned the territories west of the Mississippi River. While on a plantation near Natchez, Mississippi, Wilson came across a wounded hawk that he had never seen before. His attempt to rehabilitate the hawk ended

Wilson’s Warbler


with the raptor’s talons sunk deep into Wilson’s hand. The hawk eventually died, but Wilson described the new hawk species, calling it the Mississippi Kite. His description included information about the bird’s diet Wilson learned from a careful dissection of its belly, which was full of insects. This is the earliest known account of the Mississippi Kite’s diet.

On August 21 1813 Wilson died of dysentery at the age of 40. He is buried in Old Swedes Church in Philadelphia. During Wilson’s era, 343 species of birds were known to occur in the United States. Some of those may not have been known to Wilson, as they were previ-ously described by European ornithologists and the documentations could very well have been scattered in various European Museums. Wilson’s nine-volume American Ornithology included 264 species, 48 of which were new to science.

There are two species that occur regularly in Colorado that in-clude “Wilson” in the vernacular name.

Wilson’s Warbler (Cardellina pusilla) was discovered by Wil-son near Cape May, New Jersey. He named it “Green-black-capped Flycatcher” but it was later reclassified by the ornithologist Charles Bonaparte who then renamed it Wilson’s Warbler.

Wilson’s Snipe (Gullinago delicata) was first described by Carl Linnaeus in 1758 and given the name Common Snipe. Common snipe would later be split with the Old Word population retaining the name Common Snipe, and the New World population named in Alexander Wilson’s honor.

Further reading:Cantwell, Robert Alexander Wilson, 1961, J. B. Lippincott, Phila-

delphia and New YorkMearns, Barbara and Richard, Audubon to Xantus, 1992, Academ-

ic Press, San Diego, California

Bob Righter, [email protected]


Colorado’s Second Breeding Bird AtlasLynn E. Wickersham

Breeding Bird Atlases provide data on species distribution, breed-ing phenology, habitat use and abundance. Additionally, when they are repeated at regular intervals, Atlases can help researchers detect changes in these variables over time. Breeding Bird Atlases serve as important components of large-scale bird conservation strategies and afford natural resource professionals, academics, educators and birders information with wide-ranging applications, including wild-life management/conservation plans, environmental planning docu-ments, field research, education and birding. Because Breeding Bird Atlases require large-scale, on-the-ground efforts for data collection, most rely primarily on volunteers; thus, Atlases represent some of the best examples of citizen science.

The first wave of Breeding Bird Atlases in North America com-menced in the 1970s in the northeast. In 1980, formation of the North American Ornithological Atlas Committee (NORAC) provided an organizational framework for atlasing, and new states rapidly initi-ated Atlases across the continent. To date, more than three-quarters of U.S. states and Canadian provinces have completed a Breeding Bird Atlas. NORAC emphasizes the value of repeating Breeding Bird Atlases at regular intervals, typically 20 years, to assess changes in breeding bird distribution over time (Smith 1990). Currently, about one-quarter of states and provinces have completed, or are working to complete, their second Atlas.

Colorado initiated its first Breeding Bird Atlas in 1987, with field-work completed in 1995. Biologists and birders joined forces to collect the most comprehensive data on distribution, habitat use, breeding phenology and abundance of Colorado’s avifauna to date. Published in 1998, the 636-page Colorado Breeding Bird Atlas (Kingery 1998), hereafter Atlas I, has been widely used by wildlife and natural re-source professionals, educators and birders. Conducted from 2007 to 2012, The Second Colorado Breeding Bird Atlas (Atlas II) marked a 20-year interval from the initiation of Atlas I. Data collection was again driven primarily by volunteers, many of whom also participated in Atlas I. Numerous Atlas volunteers were also members of the Colo-rado Field Ornithologists. The primary objectives of Atlas II were to:

1. Document current distribution of breeding birds in Colorado2. Assess changes in species distribution3. Document breeding activities for new Colorado species4. Increase knowledge of habitat use and breeding phenology


Fig. 1. Change in distribution for Black Phoebe from Atlas I (1987–1995) to Atlas II (2007–2012).

Fig. 2. Change in distribution for Mountain Plover from Atlas I (1987–1995) to Atlas II (2007–2012).

5. Identify important breeding areas for threatened, endangered, sensitive, rare and secretive species

With the help of more than 60 volunteer authors, The Second Colorado Breeding Bird Atlas (Wickersham in prep) is headed for pub-

CHANGEAtlas I

Atlas II

Both Atlases

CHANGEAtlas I

Atlas II

Both Atlases


lication by the close of 2015. The book compares the results of both Atlases and presents data on changes in species distribution over time as well as updated habitat use data and breeding phenology windows, critical to wildlife and land managers across Colorado’s extensive landscape. Highlights of Atlas II include detailed accounts for 262 species; color maps, graphs and illustration; analysis of most frequently reported species per habitat type and comparison of Atlas and Breeding Bird Survey trends across habitat types. Importantly, comparative Atlas data provides evidence for some species expan-sions, for example Black Phoebe (Sayornis nigricans), as well as some declines, such as Mountain Plover (Charadrius montanus). The in-clusion of change maps in Atlas II illustrates the areas of expansion and contraction and provides a welcome addition to Atlas II (Figs. 1–2). In addition, the conversion of breeding data from tabular to graphic format simplifies the presentation of critical breeding win-dows (Fig. 3).

The Second Colorado Breeding Bird Atlas is now available for pre-order from the project website, cobreedingbirdatlasii.org. Because the Atlas has a limited audience, pre-orders are imperative in determining the print run, and the Atlas Steering Committee will facilitate only one print run. Those interested in purchasing Atlas II are strongly en-couraged to do so early to insure they will have access to this valuable resource. In addition to the book, a new Atlas II website will launch immediately following the release of the printed book. Website users

Fig. 3. Breeding phenology data for the Yellow-rumped Warbler during Atlas II (2007–2012).

13-May 31-May 18-Jun 6-Jul 24-Jul25-Apr 11-Aug 29-Aug

n=16

n=35

n=21

n=11

n=112

n=207

Feeding Fledglings

Fledged Young

Nest with Young

Occupied Nest

Courtship

Nest Building

= Median Date


may query each species for maps, block statistics, and block lists, and conversely, may search all blocks for species reported during the Atlas II period. The Atlas I website has been an indispensable tool for natu-ral resource professionals and birders alike, and Atlas II will continue to serve these users free of charge for years to come.

ACkNOwledgmeNTsAtlas II would not be possible without the tireless efforts of approximately 800 volunteers, and I sincerely thank them all. The Atlas II publication acknowledges all field workers, regional coordinators, technical committee members, records committee members, writers and data management assis-tants. Though the journey has been long and arduous, I hope that Atlas II will prove as useful as Atlas I and make all project volunteers proud to have participated.

liTerATure CiTed Kingery, H. E. (Ed.). 1998. Colorado Breeding Bird Atlas. Colorado Bird

Atlas Partnership and Colorado Division of Wildlife, Denver, CO.Smith, C. R. (Ed.). 1990. Handbook for atlasing North American birds.

Vermont Institute of Natural Science, Quechee, VT. Available at http://www.bsc-eoc.org/norac/index.jsp?targetpg=atlascont. Accessed 6 August 2015.

Wickersham, L. W. (Ed.). In prep. The Second Colorado Breeding Bird At-las. Colorado Bird Atlas Partnership and Colorado Division of Wildlife, Denver, CO.

Lynn E. Wickersham, [email protected]

Vaux’s Swift becomes Colorado’s 499th Bird SpeciesBrandon K. Percival

Birding alone on a chilly, sunny Tuesday morning on 28 April 2015, I paused near the Cottonwood Picnic area, which is on the Arkansas River, below Pueblo Reservoir dam in Pueblo County, Colorado. Swallows were everywhere, mostly Violet-green, but there were enough Barn, Cliff, Bank and Tree Swallows to keep it interest-ing. I noticed a small swift flying around with the swallows. Chim-ney Swifts (Chaetura pelagica) breed in downtown Pueblo, though I seldom see them on this part of the river, and usually not before late May or in October.


Vaux’s Swift, below the Pueblo Reservoir dam, Pueblo County, 28 April 2015. Photo by Brandon K Percival

This swift looked different to me. Chimney Swifts generally fly higher and tend to make a lot of noise. This swift was silent, fly-ing lower to the ground and it’s wing beat was different. Looking closer, I noted that the bird had a white throat and a somewhat pale rump. Compared to the Violet-green Swallows, the swift’s wing-span appeared shorter. I managed to take a few decent photos of the bird, and one confirmed white throat and pale rump. Excited that I

might be looking at a Vaux’s Swift (Chaetura vauxi), I continued to observe and photograph the swift for about ten minutes until it flew out of range.

I’ve seen Vaux’s Swift in Wash-ington State, where they’re ex-pected, and a few times in Arizona in migration. Although I didn’t have a field guide with me, I was pretty sure the bird was a Vaux’s Swift.

Seeking reassurance, I called Van Truan who confirmed the characters I’d noted in the field: light throat, pale rump and a little smaller than Chimney Swift with a shorter tail. Unable to relocate

the bird, I called Margie Joy, who birds around Pueblo a lot, and let her know to be on the lookout for this swift.

Later that morning, I circulated photos of the swift and received feedback from Chris Wood, a native Coloradan and eBird Project Leader, and Dave Siliverman who both agreed that it looked good for Vaux’s Swift. Now confident in the identification, I posted the sighting to COBirds and the CFO Facebook page. I also documented the sighting with the Colorado Birds Records Committee (CBRC). In August 2015, the CBRC voted to accept the sighting, making this first state record for Colorado!

Brandon Percival, [email protected]

Editor’s note: Congratulations to Brandon on this first state record! With the addition of Vaux’s Swift, Colorado’s state bird list now stands at 499…what species will become the state’s 500th and who will find it?


FULLY EXPOSED

Reaching Birds by BridgeBill Schmoker

Digital “super zoom” point & shoot cameras have been around for quite a while now, with their extreme zoom range in a small, relatively simple package that appeals to birders seeking an easy and affordable way to document their sightings. Many of these, however, present challenges photographing birds due to issues such as long shutter lag, difficulty autofocusing on small, active subjects and/or underwhelm-ing sensor performance. But in a world where consumer digital cam-eras even just a few years old could be considered antiques, the latest generation of low-cost cameras contain improvements making them popular among birders.

Digital cameras with large zoom ranges and many user-controlled features can be termed Bridge Cameras. This comes from the idea that they bridge the gap between the simpler point-and-shoot cam-eras and more complex Digital Single-Lens Reflex (DSLR) systems. A bridge camera has an electronic viewfinder and a built-in zoom lens, is fairly compact and reasonably affordable. Even a top-level bridge camera costs less than a birding-friendly DSLR lens alone. Bridge cameras typically have the same or similar shooting modes that a DSLR has (such as manual, aperture priority, shutter prior-ity and program-auto) as well as the ability to control ISO, color balance, exposure compensation, metering and autofocus modes. If you find yourself intimidated or confused by these options, you can take comfort in the ever-available automatic mode that bridge cameras sport. The auto mode works great as training wheels to fall back on, but I would encourage folks with a bridge camera, or DSLR for that matter, to explore and experiment with some of the more advanced modes. The advantages they offer for different shooting situations are well worth the time spent learning how and when to use them.

Depending on the make and model, a bridge camera will have some other cool tricks in store such as a palate of creative shooting modes, filters and effects. These aren’t always of great utility for bird photography but add to the versatility of the camera for landscapes and portraits. Not to be underappreciated in the birding arena is the video ability that bridge cameras boast. Their image-stabilization, along with long-lens focal length equivalent (more on that below) and built-in stereo microphones can produce movies that are im-mensely pleasing and tell much more of “the story” than single im-ages often can. For example, here’s a video I made using a bridge


Steller’s Jay, Wild Basin, Rocky Mountain National Park 24 July 2015. Photo taken with Leica V-Lux (Typ 114). Photo by Bill Schmoker

Wood Stork, Merritt Island NWR, Florida, 23 January 2015. Photo taken with Leica V-Lux (Typ 114). Photo by Bill Schmoker


camera during this year’s ABA Camp Colorado visit to Allenspark for hummingbird observation: http://bit.ly/1DW5nlD

I’ve been putting a bridge camera (Leica V-Lux Typ 114) into ex-tensive use this summer and here are some considerations and tips I’ve rounded up:

• Don’t tossyourDSLR rig (at least not yet). Bridge cameras are getting more and more amazing, but for the best images a “big rig” still delivers the goods. I like to pick my moments—if I’m out on a concerted photography effort, I’ll tote the big rig. But if I’m doing more general birding, leading a trip or aiming for video work, then I have no hesitation slinging the bridge.

• Understandthenumbers when it comes to lenses. In the bridge camera world, lenses are often marketed with figures such as “50x op-tical zoom.” This is real, but doesn’t mean 50-times magnification. Rather, it means that it has a ratio of 50 from the most zoomed to the widest setting. For example, on the venerable Canon SX50, the focal length at highest zoom is equivalent to 1200mm and the widest is equivalent to 24mm. Thus, 1200 ÷ 24 = 50x. Still amazing but at 1200mm equivalent the lens maxes out optically at the equivalent to 24 power. (For background on this, see http://bit.ly/1JW4onB.)

• Getcontroloftheautofocus area mode. For birds, you’ll want the ability to set the focus point (typically in the center of the frame) not rely on auto focus area selection. If the camera is picking the point, you’ll often end up with things like leaves and twigs in focus, not the bird.

• Highmagnification also magnifies shake. Image stabilizing sys-tems really help, but you’ll also have to rely on technique like stable shooting positions, high shutter speeds (see below) and/or tripod sup-port to get sharp shots at extreme magnification.

• Getahandleonshutterprioritymode. The higher the magni-fication and/or the more active the bird, the faster your shutter speed needs to be to get sharp shots. I suggest engaging auto-ISO (which lets the camera adjust the sensor sensitivity for you) and then dialing up the shutter speed to at least 1/1000 or even more if the light allows when shooting at high magnifications and/or fast-moving birds.

• Get a handle on aperture priority mode. When you get a wonderful close-up opportunity on a bird, dragonfly, etc., you may be disappointed to find that only part of your subject is in focus. This is because telephoto lenses inherently have a very shallow depth of field. You can counter this by dialing up your f/stop (which decreases the size of the lens aperture), giving you greater depth of field.

• Usetheelectronicviewfinder (the little viewing window) in-stead of the camera-back monitor for bird photography. It will be


easier to point the camera on target (like using binoculars) and the camera is generally more stable pressed to your face than it is held out away from your body.

• Watchoutfordigitalzoom. What looks good on your camera viewfinder or monitor might not look as good on your computer. I suggest experimenting with this to see what you think still delivers reasonable quality. You can also elect to turn off the digital zoom feature and instead use cropping in post production if you need get tighter on your subject.

• Learnthycamera. Read the manual with your camera in hand. If something doesn’t make sense, see if you can figure it out on the camera itself. Otherwise you can always Google the feature with your camera’s model name in the search field and there will likely be vid-eos, third-party reviews or tutorials. You probably won’t end up using all your camera’s features, but you’ll want to have the important stuff at your command to get the most out of a bridge camera.

When considering purchasing a bridge camera, do your homework first. As photographic subjects, wild birds can be among the most challenging. Some bridge cameras are really good at bird photogra-phy while others don’t quite make the grade. Check birding blogs, social media and word of mouth to see what works well as successive generations of bridge cameras are introduced. Many camera shops offer demo days that allow you to experience different models be-fore purchasing. For instance, the Canon SX50 has a huge following among birders (including our own Ted Floyd) while its successor the SX60 seems to be a disappointment (http://bit.ly/1DW6JNl.) I’ve been so impressed with the Leica V-Lux Typ 114 that I plan to bring it rather than my DSLR on an upcoming Arctic Ocean research cruise due to its compact size and extreme photographic versatility. (Disclaimer: As a member of the Leica Birding Team I have been loaned this camera along with other Leica optics.) There are un-doubtedly other bridge cameras out there that perform well for bird photography. You can share your experiences (and photos!) on the CFO Facebook page.

Bill Schmoker, [email protected]


2014 Grand Valley Christmas Count: 99 Western Screech-OwlsNic Korte

IntroductionWestern Screech-Owls are regularly found in 12 US states and

typically reported in nearly 150 Christmas bird count (CBC) circles including a few in Canada and Mexico. A review of eBird data con-firms Central Colorado as the Eastern limit of their distribution, with Western Screech-Owls detected in 22 of Colorado’s 64 counties. Just seven of Colorado’s 47 CBC circles reported Western Screech-Owls in 2015 and recent fieldwork (2007-2015) performed for the Colorado Breeding Bird Atlas II (Wickersham 2015) found Western Screech-Owls reported in just 13 of 1745 priority blocks (Table 1)—apparently a significant decrease from Atlas I (1987-1995, Kingery 1998).

In contrast, despite being near the eastern extent of the species’ range, the Grand Valley CBC continues to generate one of the high-est counts of Western-Screech-Owls in the nation. In 2014, a re-markable 99 birds were recorded, shattering the previous national high count of 66. This article describes how the Grand Junction CBC conducts its Screech-Owl count, and how it manages to sustain the annual high count.

Western Screech-Owls were essentially “discovered” in the Grand Valley by the late Rich Levad (Levad 1989, Levad and Korte 2006). His passion for locating the owls resulted in Grand Valley CBC re-ports with 20-30 Western Screech-Owls, well in excess of the 0-4 reported prior to 1989. Levad kept a list of natural cavities and would call the owls at a few locations in the pre-dawn, and sometimes in the early evening. On the day of the count, while he performed the typi-

Table 1. Comparison of Breeding Evidence for Western Screech-Owls Between Breeding Bird Atlas I and Atlas II in Colorado

Atlas I1987-1995

Atlas II2007-2012

Change(%)

Possible 17 7 -59

Probable 13 3 -77

Confirmed 7 3 -57

Total 37 13 -65


cal CBC duties, I would visit as many of these locations as possible to tally owls sunning themselves, or to play a call, generating the oc-casional reply or sometimes a peek from the cavity. It should be noted that unlike other small, cavity nesting owls, Western Screech-Owls rarely respond to scratching the tree with a stick.

Nest-box ProgramCoincident with the discovery of a healthy Western Screech-Owl

population in Mesa County, the human population experienced a rapid increase resulting in significant loss of farm and ranchland. The natural cavities required by the owls were being lost to development at an accelerating rate and the remaining cavities were being lost to decay and old age, with a reduced cohort of aging trees providing re-

placements (Fig. 1). Consequent-ly, a program of placing owl boxes was initiated. The program relies on school shop classes to produce the nest boxes and volunteers to place them. Today there are more than 200 nest boxes in the area with the majority located within the Grand Valley CBC Circle.

The program was success-ful and Grand Valley Western Screech-Owls quickly began us-ing the boxes. It’s not uncommon for a box to be occupied the day after placement as male Western Screech-Owls immediately claim them for their territory. Occupan-cy is typically highest in Novem-ber and December when the owls are actively establishing territories and lowest during nesting season when, for the most part, only fe-males reside in boxes. Typically the males roost concealed in near-by vegetation. Although many boxes are used for nesting, Grand Valley Western Screech-Owls continue to utilize suitable natu-ral cavities in favor of boxes as has been reported for Eastern Screech-

Fig. 1. Western Screech-Owl using a box at Walker Wildlife Area. Photo by Nic Korte


Owls (Gehlbach 1994). This observation suggests that many of the areas where boxes are used for nesting would not otherwise be productive for Western Screech-Owls.

Two examples are pre-sented to support this obser-vation. Nesting owls were detected annually in the area of Patterson and 27 ½ road in Grand Junction un-til 1999 when the nest trees and other nearby old trees were removed for real estate development. One of the de-veloped areas, The Knolls, retained a small pond and green space, but no suitable nest trees. Nest boxes were hung in elms and other small trees and have harbored nesting owls ever since.

More recently, it was recognized that the small State of Colorado Walker Wildlife Area had extensive habitat suitable for foraging, however, the trees were too small to support nesting. After the instal-lation of nest boxes in 2012, owls were occasionally observed roost-ing for two years, but this year (spring 2015) owls nested (Fig. 2).

Owl boxes are checked twice each year, once in late April or May and as many as possible on count day in December. It’s an all-volunteer effort, not a scientific study, nonetheless some generaliza-tions can be made. During December, boxes are used exclusively by Western Screech-Owls. In the spring American Kestrels and Wood Ducks use nearly as many boxes (12-20) as do owls. Starling usage fluctuates, but is significant and is likely underreported. On occa-sion House Sparrows or Northern Flickers have used boxes, but only rarely.

Box maintenance is critical. The wood can split and falling limbs frequently damage boxes. One box suffered a direct hit by lighting while occupied by an owl! Wood ducks are a desirable species but they frequently abandon some or all of their eggs. These boxes are typically not reused unless the eggs are removed. Starling usage over multiple seasons also seems to render boxes undesirable for other spe-cies.

Fig. 2. Western Screech-Owl in a natural cavity that was removed as part of a restoration project. Photo by Jackson Trappett


Box repair and cleanup is a dirty task that requires dedicated vol-unteers willing to haul ladders, tools and cleaning supplies into dif-ficult terrain. Detailed notes are collected on each box during CBCs, which helps to direct the volunteers the following spring.

Camera-on-a-PoleInitially, Levad planned an extensive banding program. To assist

with monitoring, he designed a camera-on-a-pole so that next boxes could easily be examined in the spring. As we learned more about the owls, we noticed that during the Christmas count, an individual might be observed sunning itself on the Saturday afternoon before count day, and then not only fail to respond to a call the next morn-ing, but also stay inside the hole all day. Since owl behavior is unpre-dictable, we had the idea to use a camera to check boxes on count day.

Experience with closely watched boxes and with subsequent cam-era use through the years has shown that any box may be used for a night or two—even boxes that might be unsuitable as a nest site. Hence, using the camera to check every box in the circle increased the total count by several owls. As the box program has grown, so has camera use. For the past few years we’ve assigned two teams, each with a back-up camera to prevent downtime in the event of equipment malfunction, solely to the task of checking owl boxes in the daytime. In 2014, this added 19 owls that had not responded to morning callers.

Morning Calling RoutesCalling is a relatively easy activity. All one has to do is drive to a

destination, stop and listen, play the call, listen some more, and then move to the next stop and repeat. To increase the pre-dawn calling coverage on count day, volunteers were recruited and trained. When-ever possible, new callers were paired with experienced callers as the volunteer base grew.

Although owls can respond at any time, our experience taught us that the final hour before dawn yielded the highest calling success. Volunteers are generally willing to sacrifice a little sleep in order to be in place at approximately 5:45 a.m. knowing they’ll be home in time for breakfast. For that reason, the owl count is now managed alto-gether separately from the CBC itself. Calling for Western Screech-Owls is completed early enough that there is no conflict with the day count with the exception of the two teams using cameras to check boxes.

At first calling routes were based on known locations of natural


cavities. Box locations were avoided because those would be checked with the camera. At the end of the day, the data would be reviewed to eliminate potential double-counts. As more volunteers were re-cruited, new, more complex routes were needed.

Careful study of the CBC circle habitat including many hours of scouting allowed us to plot both the known nesting territories and, based on an understanding of the Western Screech-Owl’s preferenc-es, additional likely locations. Using this technique, new routes were designed and efforts made to recruit additional volunteers to cover them. I’ve learned to give callers a lot of flexibility. Some are willing to wake early and drive sometimes several miles to their assigned route. Others simply walk out their door and call at a few locations in their neighborhood.

Initially, I devised calling routes with the sole intent of obtaining maximum coverage of the count circle. I soon realized, however, that the best way to retain volunteers was to ensure that they each had some success. Thus the next iteration of calling routes included as many of the nest boxes that were likely to be occupied as possible, and the result was a happy group of volunteers. A second benefit of this strategy was that it enabled the box camera teams to check more of the low-priority boxes, which led to the detection of owls that otherwise would have been missed.

The calling routes inevitably became more difficult to devise and check as years passed. We now rely on mapping software to create routes that combine driving efficiency and known owl locations with a minimum of overlap (Fig. 3). This work is made possible through a partnership with Colorado Mesa University and is managed by a student as part of an independent project.

For the 2014 CBC, 19 teams comprised of 51 participants reported 99 Western Screech-Owls. We determined that 34 boxes were occu-pied on count day (owls seen in or on them) with an additional five probable and 12 possible. In total, the volunteers contributed 112 hours and drove more than 350 miles.

PreparationMeticulous preparation is required to effectively deploy so many

volunteers. Each field team is given a route description and when-ever possible a detailed map that includes the calling locations. We encourage team leaders to drive their routes in advance at least once during daylight hours, both to gauge time and distance as well as to scout parking locations and determine accessibility, taking into ac-count the possibility of snow on count day.

The daytime check allows leaders to preview locations and deter-


mine if trees have been removed or otherwise altered. Fortunately, many of our leaders have performed the same routes for multiple years. In some cases, their familiarity has led to a sense of ownership and leaders have even suggested adding new box locations or have obtained landowner permission to access new areas.

Each route leader is required to report results immediately upon completion of the calling route. My wife stays by the phone with a clipboard recording results from each calling location. I later cross-check the successful sites with the master list of box locations to ensure that these locations aren’t checked with the cameras the next day. By 8 a.m. both camera teams meet at my house to review the final daytime routes. Box-checking usually continues until near dusk.

Route leaders are also encouraged to recruit additional riders since more ears generally results in more owls detected. It’s not uncommon for two owls to respond, and on rare occasions three. Additionally, Western Screech-Owls have different responses. One owl may re-spond with the traditional “bouncing ball” call, while others give an irritated bark. Having multiple observers helps ensure that all owls are counted.

Fig. 3. Example of a route map given to a calling team for the CBC.


WeatherThe two highest Grand Junction counts occurred on calm days

with heavy, overcast skies. Although hard data is lacking, my experi-ence is that calm days with a bright moon generally elicit the fewest responses. Likewise days with extreme cold, high winds or blowing snow also have been less productive.

The only certainty is that owls are unpredictable. I once followed up on a lead that an owl was using a box on my calling route, but there was no response. At first light, I approached the box and found the owl sitting in the hole oblivious to repeated calls.

Community OutreachAn unexpected benefit of the program has been the level of public

acceptance and interest. At first, outreach was limited to occasional knocks on doors to request permission to install a box in a likely area. Most homeowners have no idea that these small owls live in such close proximity with them. After learning about the birds and experiencing some sightings, many will become fiercely protective of “their” owls. Many times I’ll get a call from their neighbors seeking a nesting box for their property.

Perhaps the most satisfying aspect of public outreach has been the many friendly interactions that occur with box owners. Some are el-derly and receive few visitors. Some are simply eager to learn about what’s living in their box. They look forward to the big day when their box is checked and often will invite the volunteer in for a chat and refreshment. It’s gratifying to hear a homeowner say, “I’m always glad to see you coming.”

Each spring we hold a public banding day with a licensed bander, assisted by local volunteers, who visit several boxes to band the fledg-lings and any adult owl that is in the box. Families with children are encouraged to attend and more than 50 showed up in spring 2015. Neighbors and passers-by often take notice of the banding program and associated activities such as box checking and maintenance, providing excellent educational opportunities. Newspaper coverage adds to public awareness of local wildlife.

SummaryUntil 2014, only four CBCs had reported more than 60 Western

Screech-Owls. One of those was a Grand Valley Count and the oth-ers were from California in areas with extensive live oak, sycamore and cottonwood habitat. Nonetheless, the desert riparian and agri-cultural areas that exist within Mesa County seem to be particularly suitable for Western Screech-Owls. A multi-decade, multi-faceted


effort relying on many volunteers has resulted in the identification and augmentation of the locally high population of these birds. A well-coordinated effort of placing and maintaining nest boxes com-bined with extensive communication among volunteers and cooper-ative weather conditions resulted in a national record of 99 Western Screech-Owls detected in 2014. ACkNOwledgemeNTsAll of our work is dedicated to the late Rich Levad. We are proud of the fact that we might have taken this program beyond even his great vision for it. Thanks also to our many dedicated volunteers, without whom this extraordi-nary effort would not be possible.

liTerATure CiTedGehlbach, F.R., 1994. The Eastern Screech Owl: Life History, ecology, and

behavior in the suburbs and the countryside. (W.L. Moody Jr., Natural History Series, No.16), Texas A&M University Press, College Station, Texas.

Kingery, H. (Ed.), 1998. Colorado Breeding Bird Atlas I, Colorado Breeding Bird Atlas Partnership/Colorado Division of Wildlife, Denver, CO.

Levad, R., 1989. Western Screech-Owls in the Grand Valley. J. Colo. Field Ornithology. 27:131-132.

Levad, R., and Korte, N., 2006. Western Screech-Owls of the Grand Valley: Running Up the Score. Colorado Birds, v.40, #2, April 2006.

Wickersham, L. E. (Ed.). The Second Colorado Breeding Bird Atlas. Colora-do Bird Atlas Partnership and Colorado Parks and Wildlife, Denver, CO.

Nic Korte, [email protected]


Annual Convention of the Colorado Field OrnithologistsSalida, Chaffee County, Colorado, June 4–7, 2015Scientific Paper Session, Saturday, June 6

Christy Carello

Amber Carver. Modeling Nest-Survival in Shortgrass Steppe Pas-serines. University of Colorado, Denver, 5598 South Grant Street, Littleton, Colorado 80121; [email protected].

Avian nest survival is influenced to varying degrees by environ-mental features, some of which can be manipulated and some that are outside our control. Land managers commonly employ habitat ma-nipulation to promote population growth in target species. However, features such as weather that cannot be manipulated may exert equal or greater influence on nest survival. I estimated nest survival for three species of ground-nesting shortgrass steppe passerines in northern Colorado, and I mod-eled survival based on environ-mental features of known or sus-pected importance. I compared the applicability of two non-mu-tually-exclusive hypotheses: (1) nest survival is strongly influ-enced by weather, and (2) nest survival is strongly influenced by nest-site vegetation.

After identifying the most influential temporal variables, which would account for unmea-sured influences to survival, I fit separate sets of weather- and veg-etation-based models. Weather variables exerted equivalent moderate influence. Vegetation variables were mostly unimport-ant, except for bare ground and dead vegetation. A model con-taining both dead vegetation and bare ground best explained

The Scientific Paper Sessions are a high-light of the annual CFO Conventions and this year’s Salida Session was no exception. More than 100 avid birders hung up their binocu-lars on Saturday afternoon to enjoy presenta-tions from students, professors and amateur ornithologists. Each of the nine presenters was under pressure to keep his/her delivery under the 15-minute time limit, including listener questions! I coach my students to de-scribe their scientific work using a minimum of jargon, to accommodate a general audi-ence in a manner both understandable and compelling. CFO supports important scien-tific investigation that will further the under-standing and conservation of Colorado birds, and five of the presenters were recipients of CFO grants. If you missed the paper session this year, or just want to refresh your memory, we have compiled the abstracts in this issue for your reading pleasure. -C. Carello


survival, and it was not improved by the addition of weather variables. Nest survival declined with increasing extent of bare ground and dead vegetation. These findings support the idea that habitat manipulation can be used to promote population growth in the nesting phase.

Nora Covy. Canyon Wrens and Cliff Swallows: Observations of and Research on a Local Heterospecific Relationship. School of Biological Sciences, University of Northern Colorado, Ross Hall, Room 2480, Campus Box 92, 501 20th Street, Greeley, Colorado 80639; [email protected].

There is evidence of a locally occurring, heterospecific relation-ship between a migratory and a non-migratory avian species, based on ongoing research from 2011 through 2015. We have observed Canyon Wrens nesting and foraging in Cliff swallow nests in various locations in Larimer County at different times throughout the year. Canyon Wren occupation of suitable habitat is also positively corre-lated with presence of Cliff Swallow nest colonies. Cliff Swallow nest colonies harbor a variety of ectoparasites and other insects that could serve as a year-round food source for Canyon Wrens, increasing their chances of winter survival in this area. Furthermore, if Canyon Wrens are consuming ectoparasites, this suggests that there may be a mutu-ally beneficial relationship between these two species. In order to better understand this association, we are monitoring the occurrence of Canyon Wrens using Cliff Swallow nests as shelter and foraging lo-cations. Currently, we are assessing the relative abundance of insect prey in Cliff Swallow colonies and collecting wren fecal samples to determine the presence or absence of DNA from Cliff Swallow ecto-parasites. This project will be useful in describing behaviors and life history strategies for the Canyon Wren, a low-density, charismatic species, and it will provide novel information about how structures built by one species may influence heterospecific interactions.

Anna M. Mangan1, 2, Liba Pejchar2, and Scott J. Werner3. The Importance of Birds in Colorado’s Apple Orchards: Agents of Pest Con-trol or Fruit Depredation? 1, 3United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Na-tional Wildlife Research Center, 4101 LaPorte Avenue, Fort Col-lins, Colorado, 80521; [email protected]. 2Colorado State University, Department of Fish, Wildlife and Conservation Biology, Campus Delivery 1474, Fort Collins, Colorado 80523.

Birds provide important and sometimes irreplaceable functional roles in ecosystems and declining populations can impact ecosystems, agriculture and the economy. Organic fruit farmers face many chal-


lenges but among the most impactful are insect and animal pests. Or-chard birds have the potential to consume a major apple insect pest, the codling moth (Cydia pomonella), thereby reducing crop damage; however, birds also feed on the fruit. Our research examines these tradeoffs to understand the role of birds in apple orchards, and to help farmers make better-informed management decisions. Specifi-cally, our questions are: (1) which bird species contribute to insect pest control and fruit damage and, (2) what orchard or landscape features contribute to the rate and magnitude of these services and disservices? To answer these questions, we are investigating foraging habits and fruit damage in three organic apple orchards in the North Fork Valley of Colorado. First, to determine the relative importance of fruit- and insect-consuming birds, we are observing the time spent foraging, and quantifying the number of fruits damaged, as well as collecting fecal samples from birds captured in mist-nets. Using ge-netic sequencing, we will determine the occurrence of codling moths in these fecal samples. Second, we are estimating occupancy and density of bird species involved in pest control or fruit depredation. Third, we are using nets to exclude birds from apples and compar-ing levels of damage by birds and codling moths within and outside these exclosures. Finally, we will integrate these data to compare the rate and magnitude of pest control and damage as a function of loca-tion within the orchard, and surrounding land cover. Our findings should help advance understanding of ecological linkages between bird communities and food production in an era of unprecedented interest in the role of nature in human well-being.

Patrick Magee1 and Jonathan Coop2. Effects of Thinning Treatments on Piñon-Juniper Woodland Birds in the Arkansas River Valley. Department of Natural and Environmental Sciences, Western State Colorado University, Gunnison, Colorado 81231; [email protected], [email protected].

Piñon-juniper woodlands are the largest forest type in Colorado hosting at least 70 breeding bird species. Many birds within the piñon-juniper ecosystem are specialists including: Black-chinned Hummingbird, Gray Flycatcher, Piñon Jay, Juniper Titmouse, Be-wick’s Wren and Black-throated Gray Warbler. Recently the Royal Gorge Field Office (RGFO) of the BLM and other partners have thinned piñon-juniper woodlands to reduce potential for intense wildfires. Since 2003, some stands have been thinned with a hy-droaxe (that mulches the wood), whereas others were hand-thinned with chainsaws and subsequently the branches were scattered or piled and burned. How these treated woodlands impact bird communities


in the RGFO is unknown. We sampled 39 paired plots that each included a treated and control site. We visited each plot three times and conducted 10-minute point counts at each station (four per plot) to determine species composition and occupancy of birds. We also measured a variety of vegetation parameters to determine effects of treatments on habitat composition and structure. In 2014, 67 bird species were recorded at the 232 sample points including five piñon-juniper obligates. More species occupied treated sites than control sites. A multi-scale occupancy analysis is underway to determine if treatments influence the distribution of birds at the landscape scale and the site scale. Lark Sparrows had significantly higher occupancy in treated landscapes and used flatter sites. They occupied 15 per-cent of untreated piñon-juniper landscapes compared to 92 percent of the treated areas. The piñon-juniper obligate, Black-throated Gray Warbler showed a reversed pattern with higher occupancy in con-trol than treated landscapes, although occupancy was high in both (control=100 percent, treatment=91 percent). Results of this study will inform land managers regarding biological responses to piñon-juniper removal.

Duane Nelson. The Status of Piping Plovers and Least Terns in Colo-

Time Speaker Title of Presentation

1:30-1:35 Christy Carello, session moderator Welcome to the paper session

1:35-1:50 Duane Nelson The Status of Piping Plovers and Least Terns in Colorado

1:50-2:05 Vinson Turco Eavesdropping on other species: Nuances in avian under-standing

2:05-2:20 Anna Mangan The importance of birds in Colorado’s apple orchards: Agents of pest control or fruit depredation?

2:20-2:35 Nat Warning The link between tool use and nest construction: A new paradigm

2:35-2:50 Tyler Williams Clark’s Nutcracker seed use and limber pine meta-popula-tion dynamics

2:50-3:15 BREAK

3:15-3:30 Patrick Magee Effects of thinning treatments on piñon-juniper woodland birds in the Arkansas River Valley

3:30-3:45 Nora Covy Canyon Wrens and Cliff Swallows: Observations of and research on a local heterospecific relationship

3:45-4:00 Amber Carver Modeling nest-survival in shortgrass steppe passerines

4:00-4:15 Lynn E. Wickersham The second Colorado Breeding Bird Atlas: Final results


rado. U.S. Army Corps of Engineers and Colorado Parks and Wild-life, 342 East 6th Street, Las Animas, Colorado 81054; [email protected].

Protecting federally listed Piping Plovers and Least Terns nest-ing in Colorado requires the implementation of various management strategies. Habitat loss constitutes the primary threat, manifested by drought and non-native plant invasion to critical habitat. Second-ary threats include depredation, flooding, extreme weather events and human recreational pressure impacting nest sites. Responses to these threats have included creation of nesting islands; mechanical, manual and chemical restoration of nesting habitat and the closure and patrolling of nesting areas to the general public. In 2014 the statewide population of Piping Plovers increased to 10 pairs for the first time since monitoring began in 1990. Least Tern populations in Colorado have decreased, largely due to lakes shrinking or disappear-ing, eliminating much of their former Colorado habitat.

Vinson Turco. Eavesdropping on Other Species: Nuances in Avian Understanding. Department of Biology, Metropolitan State Univer-sity of Denver, Campus Box 53, Denver, Colorado 80217; [email protected].

Many animals are able to communicate the presence of a poten-tial predator through vocal signaling. It is known that Black-capped Chickadees (Poecile atricapilla) are able to not only advertise the presence of a potential threat but can also indicate varying levels of risk associated with a threat through a complex alarm call. While it has been shown that some birds eavesdrop on the alarm calls of oth-er species, it would greatly benefit heterospecifics living in sympatry with Black-capped Chickadees to understand the degree of danger being communicated as well—fleeing in response to non-urgent calls wastes both energy and time. In this study we performed play-backs of various chickadee alarm calls and measured the response in a number of other bird species to determine which if any are able to discern between the different degrees of urgency being com-municated. Songbirds living in close sympatry with Black-capped Chickadees have shown the greatest ability to distinguish between urgent and non-urgent calls with the most urgent calls eliciting the greatest response. Birds were significantly more likely to flee the most urgent alarm over either the less urgent call or the control. Additionally, birds were significantly more likely to exhibit alert or defensive behavior (including but not limited to fleeing) in response to only the most urgent alarm. Although the response of animals to heterospecific alarm calls has been demonstrated, the ability of one


species to interpret and respond to variations within a call has only recently begun to be explored and has potentially great implications for avian ecology.

Nat Warning. The Link Between Tool Use and Nest Construction: A New Paradigm. City of Longmont, Natural Resources Department, Longmont, Colorado; [email protected].

In studies of evolutionary biology most researchers have assigned tool use in non-humans a special biological distinction, implying that tool users inherently possess high levels of cognitive complex-ity and provide significant insights into the evolution of human cul-ture. Conversely, nest construction behaviors have typically been excluded from discussions of the evolution of tool use because the materials remain static and are not manipulated during use. Increas-ingly though, many scientists are viewing tool use as a form of con-struction behavior, recognizing that the differences between tool be-haviors and construction practices are largely arbitrary. Here I give a brief overview of nest construction behaviors in birds, emphasizing my own research on Rock Wrens (Salpinctes obsoletus), and compare nest building to using tools. I assert that nest building is of equal or greater ecological importance than tool use in animals, and that nest construction behaviors should be placed, with tool use, into the larger context of “material culture.”

Lynn E. Wickersham. The Second Colorado Breeding Bird Atlas: Final Results. San Juan Institute of Natural and Cultural Resources, Fort Lewis College, 1000 Rim Drive, Durango, Colorado 81301; [email protected].

When repeated at regular intervals, Breeding Bird Atlases pro-vide valuable data on changes in bird distribution, habitat use and breeding phenology over time. Fieldwork for Colorado’s first Breeding Bird Atlas (Atlas I) was initiated in 1987, and the results were published in 1998. Atlas I represented the state’s largest and most comprehensive study on breeding birds. Data collection for the second Colorado Breeding Bird Atlas (Atlas II) was initiated in 2007, 20 years after Atlas I, and continued through 2012. In both Atlases, field workers surveyed priority blocks uniformly dis-tributed across the state, encompassing approximately 10 m2. At-las protocol suggested three to five visits per block (~20–40 hours) over the course of one or more breeding seasons, with at least one nocturnal survey for owls and crepuscular species. During each visit, field workers recorded all species detected with associated breeding evidence and habitat codes. Breeding evidence codes


categorized each species as a Possible, Probable or Confirmed breeder within each block.

More than 700 volunteers participated in Atlas II, logging more than 54,000 field hours and recording over 195,000 breeding obser-vations. Field workers spent an average of 28.1 person-hours per pri-ority block, compared with 38.6 in Atlas I. Despite the reduction in effort, Atlas II reported about 14 percent more observations and documented 11 more species than Atlas I. Atlas II field workers re-ported 14 “new” species (not reported in Atlas I) but failed to docu-ment 11 rare species reported in Atlas I. Comparing the number of priority blocks with breeding evidence per species, 56.6 percent of species showed apparent gains, 40.7 percent showed losses and 2.7 percent remained the same. The top five most widely reported species included Mourning Dove, American Robin, Red-tailed Hawk, West-ern Meadowlark and Brown-headed Cowbird. Atlas II data suggests notable range expansions for Wild Turkey, Osprey, Black-chinned Hummingbird, Black Phoebe and Great-tailed Grackle, to name a few, and possible declines for Mountain Plover, Long-billed Curlew, Western Screech-Owl, Lewis’s Woodpecker and Belted Kingfisher.

Tyler Williams1 and Diana Tomback2. Clark’s Nutcracker Seed Use and Limber Pine Meta-population Dynamics.

1901 North Sherman Street, Apartment #708, Denver, Colorado, 80203; [email protected]. 2Department of Integrative Biology, University of Col-orado, Campus Box 171, P.O. Box 173364, Denver, Colorado, 80217-3364; [email protected].

The Clark’s Nutcracker (Nucifraga columbiana) is an iconic species of the American West because of its importance as a seed disperser of several high-elevation pines including Limber Pine (Pinus flexilis). Its diet consists primarily of conifer seeds. Within Colorado the large seeds of Limber Pine are preferred over other conifer seeds.

Limber Pine stands comprise meta-populations—i.e. regional populations composed of local populations subject to extinction, colonization and re-colonization. We are studying how the Limber Pine meta-population in Rocky Mountain National Park (RMNP) is maintained by long-distance seed dispersal (colonization) by the nutcrackers, and how disturbance might lead to local population ex-tinctions. Historically, fire and ecological succession primarily caused local population extinctions, but current threats for the RMNP Lim-ber Pine meta-population include mountain pine beetle (Dendroc-tonus ponderosae) outbreaks, wildfires and White Pine blister rust (a non-native pathogen, Cronartium ribicola). Extensive tree mortality will result in the loss of an important nutcracker food source and


may reduce nutcracker seed dispersal, complicating meta-population persistence.

Our primary goal is to clarify the dynamics of the RMNP Limber Pine meta-population, focusing on the factors that affect coloniza-tion. From mid-June to late October 2014, we investigated nutcracker dietary preferences within RMNP by examining 1) Cone production via distance sampling from five Limber Pine stands, three Ponderosa Pine (Pinus ponderosa) stands and three Douglas Fir (Pseudotsuga menziesii) stands: conifers with seeds that nutcrackers routinely use. 2) Nutcracker stand visitation via point counts. 3) Nutcracker seed harvest and caching by focal behavior sampling. This information would identify the conifer species responsible for keeping nutcrackers within RMNP and could serve as a proof of concept that nutcrack-ers are the primary seed disperser of Limber Pine within RMNP. We have also constructed the RMNP Limber Pine meta-population from GIS layers.

The 2014 data indicate that Limber Pine and Ponderosa Pine seed productivity ranged from high to low throughout our study stands, while Douglas Fir productivity was primarily low. Nutcrackers be-gan foraging on Limber Pine in early August and caching of Limber Pine seeds commenced in early September. Nutcracker foraging and caching observations shifted from Limber Pine to Ponderosa Pine in October. No foraging or caching was observed for Douglas Fir. Be-cause both pines do not produce cones every year, together they are a significant resource for nutcrackers and are important for keeping them within RMNP.

In 2015 we will radio-track nutcrackers to collect data on nut-cracker home range sizes, seed dispersal distances and caching loca-tions for meta-population connectivity information.

Christy Carello, [email protected]


NEWS FROM THE FIELD

Spring 2015 (March–May)David Dowell

“News from the Field” contains reports of rare birds found in Colorado. These reports are compiled from eBird (ebird.org), the COBirds listserv ([email protected]) and the West Slope Birding Network ([email protected]). The reports contained herein are largely unchecked and the editors do not necessarily vouch for their authenticity. Species in capitals are those for which the Colorado Bird Records Committee (CBRC) requests documen-tation. Please submit your sightings of these “review” species through the CFO website at coloradobirdrecords.org.

Season OverviewColorado birders will remember spring 2015 for the rain as much

as for the birds. Rain fell almost daily in many locations during the first three weeks of May 2015. As a result, Colorado experienced its wettest May in the 121 years of precipitation records dating back to 1895 (www.ncdc.noaa.gov/temp-and-precip/us-maps/1/201505#us-maps-select). Portions of eastern and northeastern Colorado received over 10 inches of rain, which is more than five times the average amount, and western counties also received above normal rainfall.

The persistent rains affected where the birds and the birders went. Flooding closed roads and inundated state wildlife areas, particularly

National Oceanic and Atmospheric Administration analysis of May 2015 precipita-tion (inches) in Colorado and surroundings.


near rivers such as the South Platte. Crow Valley Recreation Area in Weld, a traditional May hotspot for birders seeking eastern migrants, closed in late May after the intermittent Crow Creek became a river.

Birders encountered a few local fallouts in late April and early May during the onset of the rainy period, but more often they re-ported finding fewer migrating land birds than usual. Nevertheless, the species list compiled from reports across the state in spring 2015 is impressive, and includes 38 warbler species.

Alder Flycatchers were reported at 13 locations in eastern Colo-rado in May, with multiple birds found in several locations. The high number of sightings of this species, which is on the state review list, is unprecedented. The first sighting, on May 2, is also earlier than previously accepted records.

Noteworthy sightings of individual birds in spring 2015 include Vaux’s Swift in Pueblo, a first state record; Mottled Duck in Pueblo, a candidate second state record to be reviewed by the CBRC; Zone-tailed Hawk in Kit Carson (two previously accepted records); West-ern Gull in Delta (four accepted records); Common Ground-Dove in Delta (five accepted records); Painted Redstart in Montrose (seven accepted records); Black-chinned Sparrow in Mesa (six accepted records); California Condors (tagged birds “N8” in Montezuma and “N1” in El Paso); Lucy’s Warbler in Weld, one of only a few records in eastern Colorado; and Yellow-throated Warbler in La Plata, a first record for western Colorado.

In the list of reports below, county names are italicized and the fol-lowing abbreviations are used: CFO – Colorado Field Ornithologists; m.ob. – many observers; MA – Management Area; NM – National Monument; NP – National Park; NWR – National Wildlife Refuge; Res. – Reservoir; SP – State Park; SWA – State Wildlife Area.

BRANT (Black): One at Monte Vista NWR, Rio Grande, 16 Mar – 27 Apr (Deb Callahan, m.ob.).

Trumpeter Swan: As many as 5 near Hayden, Routt, 4 Jan – 6 Mar (Nancy Merrill, Tresa Moulton). 1 at Fruitgrowers Res., Delta, 9 Mar (Ev-elyn Horn).

Tundra Swan: Two at Holcim Wetlands near Florence, Fremont, 15 Feb - 11 Mar (Rich Miller, m.ob.). One east of Pueblo, Pueblo, 25 Mar (Clark Jones).

MOTTLED DUCK: One at Lake Beckwith in Colorado City, Pueblo, 10 Apr (David Silverman).

Long-tailed Duck: Reports from Alamosa, El Paso, Lake, Larimer, Mesa, Park and Weld, 1 Mar – 14 Apr.

Pacific Loon: One near Nucla, Montrose, 3 – 6 Apr (Coen Dexter and Brenda Wright). One at High-line Lake SP, Mesa, 23 Apr (Denise and Mark Vollmar).

Red-necked Grebe: One at Pueb-lo Res., Pueblo, 1 Feb – 22 Apr (Mark


Peterson, m.ob.). One at Fossil Creek Res., Larimer, 21 Apr (Bobbie Til-mant). One at Barr Lake SP, Adams, 9 May (David Hill, Amy Morton, Karen Drozda, Cynthia Madsen).

NEOTROPIC CORMORANT: One near Windsor, Weld, 6 Apr (Steve Mlodinow).

BROWN PELICAN: One at St. Vrain SP, Weld, 6 Apr (Dawn Al-bright).

Black-crowned Night-Heron: Two hundred at MacFarlane Res., Jackson, 25 May (Charles Hundertmark).

Glossy Ibis: Two at Pastorius Res., La Plata, 1 – 3 May (Susan Allerton, Catherine Ortega, m.ob.); rare in western Colorado. Five at Red Lion SWA, Logan, 16 May (Alec Hopping, David Dowell). Other reports from Kit Carson, Larimer, Otero, Washington and Weld, 24 Apr – 18 May.

California Condor: One south of Dolores, Montezuma, 16 Apr (Franz Carver). One in Black Forest, El Paso, 31 May.

COMMON BLACK HAWK: One juvenile at Cottonwood Canyon, Baca, 13 – 14 Apr (Michael O’Brien, Brian Gibbons, m.ob.). One adult at Pueblo Res., Pueblo, 23 Apr (Brandon Percival).

Broad-winged Hawk: One at Carnero Pass Road, Saguache, 20 May (John Cobb); rare in western Colorado. Other reports from Adams, Arapahoe, Baca, Bent, Boulder, Den-ver, Douglas, El Paso, Elbert, Fremont, Jefferson, Kiowa, Kit Carson, Larimer, Lincoln, Logan, Montrose, Phillips, Prowers, Pueblo, Sedgwick, Washing-ton, Weld and Yuma, 4 Apr – 31 May.

ZONE-TAILED HAWK: One in

Burlington, Kit Carson, 8 Apr (Riley and Heather Morris).

Whimbrel: Reports from Bent, Crowley, Denver, El Paso, Elbert, Jef-ferson, Kiowa, Otero, Pueblo and Weld, 20 Apr – 18 May.

HUDSONIAN GODWIT: One at Holbrook Res., Otero, 27 Apr (Stanley Oswald). One near Hasty, Bent, 4 – 9 May (John Drummond, Lynne Miller, m.ob.). One at Lower Latham Res. and Beebe Draw, Weld, 1 – 8 May (Bob Righter, group led by Joey Kellner).

RED KNOT: One at John Martin Res., Bent, 9 May (Nick Komar).

Dunlin: One at Monte Vista NWR, Rio Grande, 17 May (Heidi Retherford); rare in western Colora-do. Other reports from Adams, Bent, Crowley, Denver, Kiowa and Weld, 1 Mar – 17 May.

Laughing Gull: One adult in La-mar, Prowers, 26 Apr (Dave Leather-man). One adult at Boyd Lake SP, Larimer, 20 May (Nick Komar).

Mew Gull: One at Windsor Lake,

Common Black-Hawk, Cottonwood Canyon, Baca County, 14 April 2015. Photo by Janeal Thompson


Weld, 11 Mar (Mark Minner-Lee). One at Seeley Res., Weld, 11 Mar (Steve Mlodinow). One at Marston Res., Denver, 18 Mar (Alec Hopping).

WESTERN GULL: One at Fruit-growers Res., Delta, 9 May (Leo Mill-er).

ICELAND GULL (Kumlien’s): One at South Platte River near Thornton, Adams, 6 – 8 Mar (David Dowell, m.ob.). One sub-adult Ice-land/Thayer’s at Prewitt Res., Wash-ington, 8 Mar (group led by Joey Kell-ner). one at Jackson Res., Morgan, 20 Apr (David Dowell).

GLAUCOUS-WINGED GULL: One immature at Black Hollow Res., Weld, 11 Mar (Steve Mlodinow). One immature at Lower Latham Res., Weld, 16 Apr (Nick Moore, Steve Mlodinow).

ARCTIC TERN: One at Tim-nath Res., Larimer, 24 – 29 May (Da-vid Wade, Austin Hess, Nick Komar, m.ob.).

COMMON GROUND-DOVE: One in Paonia, Delta, 13 May (Jason Bea-son); second western Colorado record.

BLACK-BILLED CUCKOO: One at Chico Basin Ranch, El Paso, 25 May (Brandon Percival).

Boreal Owl: Reports from Delta, Jackson, Mesa, Routt and Summit, 6 Mar – 27 May.

VAUX’S SWIFT: One at Pueblo Res., Pueblo, 28 Apr (Brandon Per-cival); first state record.

RUBY-THROATED HUM-MINGBIRD: One at Stulp Ranch near Lamar, Prowers, 4 – 5 May (Jane Stulp, m.ob.).

Calliope Hummingbird: One in Grand Junction, Mesa, 24 Apr (Ron Lambeth); a rare sighting in spring in Colorado and a very early arrival.

ACORN WOODPECKER: One in Colorado Springs, El Paso, 20 Dec – 7 Mar (Marty Wolf, m.ob.).

Yellow-bellied Sapsucker: One at Lamar Community College and Wil-low Creek Park, Prowers, 14 – 28 Mar (Glenn Walbek, Mark Peterson, Da-vid Tønnessen, m.ob.). One at Wray Fish Hatchery, Yuma, 21 Mar (David Dowell). One at Stulp Ranch near La-mar, Prowers, 31 Mar (Jane Stulp).

Dusky Grouse, Lookout Mountain, Jef-ferson County, 25 March 2015. Photo by Janeal Thompson

Snowy Plover, Sweetwater Reservoir, Kiowa County, 20 April 2015. Photo by Dave Leatherman


GYRFALCON: One near Glade Park, Mesa, 10 Mar (Mike Henwood, Eileen Cunningham).

EASTERN WOOD-PEWEE: One at Stulp Ranch near Lamar, Prowers, 8 May (Jane Stulp). One at Fountain Creek Regional Park, El Paso, 19 May (Bill Maynard). One near Loveland, Larimer, 22 May (Sean Walters). One at Lamar Community College, Prowers, 26 May (Dorothy Russell).

YELLOW-BELLIED FLYCATCH-ER: One in Florence, Fremont, 21 May (Brandon Percival). One at Holyoke Cemetery, Phillips, 23 May (Steve Lar-son, Steve Mlodinow).

ALDER FLYCATCHER: One near Laird, Yuma, 2 May (Sue Riffe, David Dowell). One at Prewitt Res., Logan, 15 May (Joey Kellner, Kathy Mihm Dunning, Norman Erthal, Alec Hopping). One near Eads, Kiowa, 20 May (Steve Mlodinow, Steve Larson, Van Remsen). Two at Hale Ponds in South Republican MA, Yuma, 21 May

(Steve Mlodinow, Steve Larson, Van Remsen). One at Flagler Res. SWA, Kit Carson, 22 – 29 May (Glenn Wal-bek, m.ob.). One at Lee Martinez Park in Fort Collins, Larimer, 24 May (Nick Komar). As many as 3 in Ovid, Sedgwick, 24 – 25 May (Steve Larson, Steve Mlodinow, Van Remsen, Wil-liam Kaempfer, David Dowell). As many as 2 at Lion’s Club Fishin’ Hole in Holyoke, Phillips, 24 – 25 May (Da-vid Dowell, William Kaempfer). One at Sand Draw SWA, Sedgwick, 24 May (Steve Larson, Steve Mlodinow, Van Remsen). One at Cherry Creek SP, Arapahoe, 24 May (Glenn Walbek, Gene Rutherford, Alec Hopping). One at Chico Basin Ranch, Pueblo, 25 May (Alec Hopping, Brandon Per-cival, Norm Lewis). One at DePoorter Lake in Julesburg, Sedgwick, 25 May (William Kaempfer, David Dowell). One at Glenmere Park in Greeley, Weld, 27 May (Steve Mlodinow).

Vermilion Flycatcher: One male

Mountain Plover, CR 38 near Holly, Prowers County, 23 April 2015. Photo by Janeal Thompson

Hudsonian Godwit, Verhoeff Ditch, Hasty, Bent County, 4 May 2015. Photo by Janeal Thompson


near Pueblo Res. in Rock Canyon, Pueblo, 5 Apr (Pearl Sandstrom-Smith, Cliff Smith, m.ob.). One fe-male at Cherry Creek SP, Arapahoe, 21 Apr (Cheri Phillips).

Scissor-tailed Flycatcher: One at Chatfield SP, Douglas, 1 May (Paul Schlagbaum, m.ob.). One in Walsh, Baca, 5 – 18 May (Janeal Thompson, Jane Stulp, Gene Rutherford). One at Cherry Creek SP, Arapahoe, 5 – 12 May (Steven Kennedy, m.ob.). One at Clear Springs Ranch south of Foun-tain, El Paso, 14 May (Aaron Driscoll, Mark Peterson, Peter Gaede). One near La Veta, Huerfano, 30 May (Polly Wren and Paul Neldner).

White-eyed Vireo: One at Lamar Community College, Prowers, 25 Apr – 2 May (Glenn Walbek, Mark Peter-son, m.ob.). One at Barr Lake SP, Ad-ams, 2 – 3 May (Adam Vesely, m.ob.). One at DeWeese Res., Custer, 30 Apr (Rich Miller) and 1 at Pike’s Stock-ade, Conejos, 27 May (Lisa Rawinski);

very rare west of the Front-Range mountains.

Yellow-throated Vireo: One at Roselawn Cemetery near Pueblo, Pueblo, 2 May (Brandon Percival). One at Fountain Creek Regional Park, El Paso, 3 May (David Tønnes-sen, Mark Peterson). One at Lamar Community College, Prowers, 5 – 9 May (Brandon Percival, group led by William Kaempfer). One at Picture Canyon, Baca, 10 May (Tom Thom-son, Mark Amershek, Scott Manwar-ing, Austin Hess). Three at Welches-ter Tree Grant Park near Golden, Jefferson, 15 May (Robert Martinez). One at Flagler Res. SWA, Kit Car-son, 18 May (Glenn Walbek). 1 at Prospect Ponds Natural Area in Fort Collins, Larimer, 20 May (Sue Riffe). One at Salyer, McMurry and Magpie Meander Natural Areas in Fort Col-lins, Larimer, 20 May (Sue Riffe). One at Crow Valley Campground, Weld, 16 – 20 May (Josh Bruening, Derek Hill,

Stilt Sandpiper, Valco Ponds, Pueblo County, 2 May 2015. Photo by Janeal Thompson

Eastern Phoebe, Cottonwood Canyon, Baca County, 14 April 2015. Photo by Janeal Thompson


m.ob.). One at Lions Park in Laporte, Larimer, 22 May (Nick Komar, David Wade). One at Chatfield SP, Jefferson, 22 May (Loch Kilpatrick, David Sud-djian). One at Rocky Mountain NP, Larimer, 26 May (PJ Ross).

Blue-headed Vireo: One at Two Buttes SWA, Baca, 3 May (group led by Joey Kellner). One in Colo-rado Springs, El Paso, 10 May (David Tønnessen). One at Welchester Tree Grant Park near Golden, Jefferson, 23 May (Mark Chavez).

Philadelphia Vireo: One at Chat-field SP, Jefferson, 23 May (Renee and Jesse Casias).

Winter Wren: As many as 3 at Brush SWA, Morgan, 28 Feb – 21 Mar (David Dowell, m.ob.). One at Two Buttes SWA, Baca, 21 Mar (Joey Kell-ner, Kathy Mihm Dunning, Tim Smart, Norman Erthal). One at Chatfield SP, Douglas, 22 Mar (Joey Kellner, David Suddjian). One at Rocky Mountain NP, Larimer, 23 May (James Nelson).

Carolina Wren: One near Higbee, Otero, 5 Apr (David Dowell).

Veery: Reports from Arapahoe, Baca, Bent, Boulder, El Paso, Larimer, Lincoln, Phillips, Prowers, Pueblo, Sedg-wick, Washington, Weld and Yuma, 6 – 30 May.

Gray-cheeked Thrush: One in Ar-riba, Lincoln, 28 Apr (Glenn Walbek). One at Chico Basin Ranch, Pueblo, 9 May (Michele Steber). One in rural Arapahoe, 11 May (Gene Rutherford). One at Crow Valley Campground, Weld, 11 May (Steve Mlodinow). One at Melody Tempel Grove, Bent, 11 May (John Drummond). One near Simla, Elbert, 11 May (David Sud-djian). One in Cañon City, Fremont, 16 May (John Drummond, Brandon Percival).

Swainson’s Thrush (Russet-backed): One at Melody Tempel Grove, Bent, 19 May (Steve Mlodi-now). One in Boulder, Boulder, 21 May (Nick Moore).

Black Phoebe, Boulder Creek and 75th St, Boulder County, 6 April 2015. Pho-to by David Dowell

Scissor-tailed Flycatcher, two miles east of La Veta on CR 358, Huerfano County, 3 May 2015. Photo by Polly Wren Neldner


Wood Thrush: One at Flagler Res. SWA, Kit Carson, 8 May (Joey Kell-ner, Norman Erthal, Charles Law-rence, Kathy Mihm Dunning, Cheryl Teuton). One at Chico Basin Ranch, El Paso, 20 May (Richard Bunn, John Drummond, Bill Maynard). One in Fort Collins, Larimer, 30 May (Greg Levandoski).

Gray Catbird: Forty-eight at Brett Gray Ranch, Lincoln, 22 May (Kathy Mihm Dunning, Joey Kellner).

Curve-billed Thrasher: One at Confluence Park in Delta, Delta, 15 May (Andrea Robinsong); rare in western Colorado.

Chestnut-collared Longspur: A whopping 1,875 near Genoa, Lincoln, 15 Apr (Glenn Walbek).

McCown’s Longspur: Three near Rabbit Ears Pass, Routt, 17 Apr (An-drew Spencer); rare in western Colo-rado.

Worm-eating Warbler: One at Pi-nello Ranch near Colorado Springs,

El Paso, 2 May (Susan Luenser, Gloria Nikolai). One at Sinton Pond in Col-orado Springs, El Paso, 13 – 16 May (Dan Stringer, m.ob.) One at Brett Gray Ranch, Lincoln, 15 – 30 May (Glenn Walbek, Peter Gaede, Mark Peterson, Kathy Mihm Dunning). One at Prewitt Res., Washington, 17 May (David Dowell). One at Salyer, McMurry and Magpie Meander Natu-ral Areas in Fort Collins, Larimer, 19 – 20 May (David Wade, m.ob.)

Blue-winged Warbler: One at Fla-gler Res. SWA, Kit Carson, 28 Apr (Glenn Walbek). One at Welchester Tree Grant Park near Golden, Jeffer-son, 13 May – 17 June (Mark Chavez, m.ob.).

GOLDEN-WINGED WARBLER: One at Main Res. in Lakewood, Jef-ferson, 25 Apr (Art Hudak, Alec Hop-ping). One in Cañon City, Fremont, 16 – 21 May (Robb Hinds, Brandon Percival). One at Flagler Res. SWA, Kit Carson, 16 May (Peter Gaede, Mark Pe-

Cassin’s Kingbird, Boulder Open Space, Boulder County, 22 May 2015. Photo by Peter Burke

Yellow-throated Vireo, Fountain Creek Regional Park, El Paso County, 3 May 2015. Photo by Bill Maynard


Dunlin, South Platte River, Adams County, 6 March 2015. Photo by Da-vid Dowell

Short-eared Owl, Bar 10 Road, El Paso County, 6 May 2015. Photo by Bill Maynard

Golden-crowned Kinglet, Stulp’s Farm, Prowers County, 2 April 2015. Photo by Janeal Thompson

Yellow-billed Cuckoo, Northern Colo-rado Environmental Learning Center, Larimer County, 21 May 2015. Photo by Dave Leatherman

Least Tern, Northgate Reservoir, Prow-ers County, 2 May 2015. Photo by Ja-neal Thompson

Gray Flycatcher, Ryssby Church, Boul-der County, 22 May 2015. Photo by Peter Burke


Chestnut-sided Warbler, Chico Basin Ranch, Pueblo County, 11 May 2015. Photo by Bill Maynard

Prothonotary Warbler, Chico Basin Ranch, El Paso County, 29 May 2015. Photo by Bill Maynard

Magnolia Warbler, Chico Basin Ranch, El Paso County, 18 May 2015. Photo by Bill Maynard

Blackpoll Warbler, Pioneer Park, Ster-ling, Logan County, 20 May 2015. Photo by Dave Leatherman

Northern Mockingbird, CU East Cam-pus, Boulder County, 24 May 2015. Photo by Peter Burke

Black-throated Blue Warbler, Hanover Road, El Paso County, 30 May 2015. Photo by Bill Maynard


American Redstart, South Mesa Trail-head, Boulder County, 22 May 2015. Photo by Peter Burke

Northern Parula, Stulp Farm, Prowers County, 29 April 2015. Photo by Dave Leatherman

Kentucky Warbler, Lamar Community College Woods, Prowers County, 23 April 2015. Photo by Janeal Thompson

Summer Tanager, Northern Colorado Environmental Learning Center, Lar-imer County, 26 May 2015. Photo by Dave Leatherman

Mourning Warbler, Chico Basin Ranch, El Paso County, 18 May 2015. Photo by Bill Maynard


Painted Bunting, Clear Spring Ranch, El Paso County, 3 May 2015. Photo by Bill Maynard

Orchard Oriole, Chico Basin Ranch, El Paso County, 25 May 2015. Photo by Bill Maynard

Purple Finch, 6th Street, Las Animas, Bent County, 4 March 2015. Photo by Janeal Thompson

Rose-breasted Grosbeak, Melody Tem-ple’s Grove, Bent County, 28 April 2015. Photo by Dave Leatherman

Bobolink, Reservoir Ridge, Fort Collins, Larimer County, 17 May 2015. Photo by Janeal Thompson


terson, Kara Carragher, Lisa Edwards). One hybrid with Blue-winged Warbler (“Brewster’s Warbler”) near Loveland, Larimer, 21 May (Sean Walters, David Wade, Austin Hess, Denise Bretting). One at Butterfly Woods Natural Area in Fort Collins, Larimer, 23 May (John Shenot).

Black-and-white Warbler: Reports from Arapahoe, Baca, Bent, Douglas, El Paso, Elbert, Jefferson, Kit Carson, Larimer, Lincoln, Prowers and Pueblo, 1 – 29 May.

Prothonotary Warbler: One at Picture Canyon, Baca, 9 – 10 May (group led by William Kaempfer, m.ob.). One at Lamar Community College, Prowers, 11 – 23 May (Janeal Thompson, Jane Stulp, m.ob.). One at Chico Basin Ranch, El Paso, 28 – 29 May (Victoria Wheeler, Anton Morri-son, Brandon Percival, Richard Bunn, Lisa Edwards).

Tennessee Warbler: Reports from Adams, Arapahoe, Baca, Boulder, El Paso, Elbert, Jefferson, Kit Carson, Lar-imer, Lincoln, Logan, Phillips, Prowers, Pueblo, Sedgwick, Weld and Yuma, 26 Apr – 26 May.

Orange-crowned Warbler: One hundred ninety-one at Flagler Res. SWA, Kit Carson, 26 Apr (David Dowell).

LUCY’S WARBLER: One at Eaton Cemetery, Weld, 10 – 14 May (Dave Leatherman, m.ob.).

Nashville Warbler: Reports from Arapahoe, Baca, Cheyenne, El Paso, Elbert, Jefferson, Kit Carson, Montezu-ma, Prowers and Pueblo, 15 Apr – 22 May.

MOURNING WARBLER: One at Melody Tempel Grove, Bent, 8

May (Duane Nelson). One at Lamar Community College, Prowers, 11 May (Dorothy Russell). One near Agate, Elbert, 11 May (David Suddjian). One at Salyer, McMurry and Magpie Me-ander Natural Areas in Fort Collins, Larimer, 19 – 21 May (Dave Leather-man, m.ob.). One at Chico Basin Ranch, El Paso, 20 – 25 May (John Drummond, m.ob.).

Kentucky Warbler: One at Lamar Community College, Prowers, 23 Apr (Jeannie Mitchell, Aaron Shipe). One at Stulp Ranch near Lamar, Prowers, 31 May (Jane Stulp)

Hooded Warbler: One female at Chico Basin Ranch, El Paso/Pueblo, 29 Apr – 27 May (Nancy Gobris, m.ob.). One at Melody Tempel Grove, Bent, 8 – 10 May (group led by William Kaempfer). One male south of Limon, Elbert, 18 May (David Suddjian).

CAPE MAY WARBLER: One female at Lake Hasty in John Martin Res. SP, Bent, 6 – 11 May (Brandon Percival, Gene Rutherford, Nick Ko-mar, Jeannie Mitchell, John Drum-mond).

Northern Parula: One near Cres-tone, Saguache, 14 May (John Cobb). One at Loudy-Simpson Park near Craig, Moffat, 17 May (Tom and Kay McConnell). One near Gunnison, Gunnison, 25 May (Tasha Blecha); rare in western Colorado. Other re-ports from Arapahoe, Baca, Bent, Boul-der, Douglas, El Paso, Elbert, Huerfano, Jefferson, Kiowa, Kit Carson, Larimer, Lincoln, Phillips, Prowers, Pueblo and Weld, 21 Apr – 26 May.

Magnolia Warbler: Reports from Arapahoe, Bent, Boulder, El Paso, El-bert, Jefferson, Larimer, Lincoln, Prow-


Bell’s Vireo, Valco Ponds, Pueblo County, 31 May 2015. Photo by Bill Maynard

ers, Pueblo, Washington, Weld and Yuma, 15 – 31 May.

Blackburnian Warbler: One northwest of Kit Carson, Cheyenne, 1 May (group led by Joey Kellner). One at Stalker Lake near Wray, Yuma, 2 May (Sue Riffe). One at Navajo Res., Archuleta, 21 May (James Beatty); very rare in western Colorado.

Chestnut-sided Warbler: One at Loudy-Simpson Park near Craig, Moffat, 21 May (Jan Leonard) and 1 in Durango, La Plata, 24 May (Susan Allerton, James Beatty, Riley Morris); rare in western Colorado. Other re-ports from Arapahoe, Denver, El Paso, Elbert, Fremont, Jefferson, Kiowa, Kit Carson, Larimer, Logan, Prowers, Pueblo and Yuma, 6 – 30 May.

Blackpoll Warbler: Reports from Arapahoe, Baca, Bent, Boulder, Broom-field, El Paso, Elbert, Jefferson, Kiowa, Kit Carson, Larimer, Lincoln, Logan, Morgan, Phillips, Prowers, Pueblo, Sedgwick, Washington, Weld and Yuma, 2 – 29 May.

Black-throated Blue Warbler: Singles at Melody Tempel Grove, Bent, 4 May (Brandon Percival) and 19 May (Duane Nelson). One at Stulp Ranch near Lamar, Prowers, 7 May (Jane Stulp). One at Lamar Community College, Prowers, 9 May (group led by William Kaempfer, Nick Komar). One at Fort Lupton, Weld, 9 May (Jan DeSanti). One at Fountain Creek Regional Park, El Paso, 10 May (group led by Ken Pals and Ted Floyd). One at Chatfield SP, Douglas, 12 May (David Suddjian). Singles in Colo-rado Springs, El Paso, 21 May (David Tønnessen) and 25 May (Gail Baker). One along Hanover Road near Chico Basin Ranch, El Paso, 30 May (Rich-ard Bunn, Brandon Percival).

Palm Warbler: Reports from Arap-ahoe, Baca, Bent, Boulder, Denver, El Paso, Elbert, Kit Carson, Lincoln, Mor-gan, Prowers and Pueblo, 25 Apr – 20 May.

Pine Warbler: One in Pueblo, Pueblo, 17 Mar (Van Truan). One at Barr Lake SP, Adams, 20 May (Chris-topher Rustay).

Prairie Warbler, Chico Basin Ranch, El Paso County, 29 April 2015. Photo by Bill Maynard


Yellow-throated Warbler: One in Durango, La Plata, 6 – 11 May (Kris-ti Dranginis, Andrea Avantaggio, m.ob.); first western Colorado record.

PRAIRIE WARBLER: One at Chico Basin Ranch, El Paso, 29 Apr – 3 May (Nancy Gobris, m.ob.)

Townsend’s Warbler: Reports from Denver, El Paso, Elbert, Fremont, Jefferson, Kit Carson, Lincoln, Mon-tezuma, Park, Prowers, Pueblo and Washington, 26 Apr – 20 May.

Black-throated Green Warbler: One at Melody Tempel Grove, Bent, 1 – 4 May (group led by Joey Kellner, m.ob.). As many as 2 at Brett Gray Ranch, Lincoln, 13 – 18 May (Steve Mlodinow, Mark Peterson, Peter Gaede). One at Chico Basin Ranch, El Paso, 25 May (Brandon Percival).

PAINTED REDSTART: One at Black Canyon of the Gunnison NP, Montrose, 15 Apr (Matthew DeSaix).

EASTERN TOWHEE: One first-year male at Tamarack Ranch SWA, Logan, 3 Jan – 14 Mar (Steve Lar-son, Loch Kilpatrick, Glenn Walbek, m.ob.); possibly a hybrid with Spotted Towhee. One female at Chico Basin Ranch, El Paso, 11 Apr (John Drum-mond). One female at Fox Ranch, Yuma, 21 May (Steve Larson, Steve Mlodinow). One female at Brush SWA, Morgan, 25 May (David Dow-ell).

BLACK-CHINNED SPAR-ROW: One at Colorado NM, Mesa, 2 May (Forrest Luke, John Weier, Garry Budyk).

BAIRD’S SPARROW: One at Pueblo Res. SWA, Pueblo, 16 Apr (Brandon Percival).

Golden-crowned Sparrow: One

adult, present for its fifth consecutive winter, at Teller Farm and Lakes, Boul-der, 30 Oct – 18 Apr (David Dowell, m.ob.). One adult, present for its sixth winter, at Red Rocks Park, Jefferson, 1 Nov – 8 Mar (Cyndy Johnson, m.ob.). One at Running Deer and Cotton-wood Hollow Natural Areas, Larimer, 8 Mar (David Wade).

Summer Tanager: Reports from Baca, Bent, Boulder, El Paso, Elbert, Kiowa, Kit Carson, Larimer, Lincoln, Montezuma, Phillips, Pitkin, Prowers, Pueblo and Routt, 1 – 29 May.

Scarlet Tanager: One male in Col-orado Springs, El Paso, 22 May (Sha-ron Milito). One male near Milliken, Weld, 27 May (Steve Mlodinow). One male near Limon, Elbert, 31 May (Da-vid Suddjian).

Black-headed Grosbeak: Forty-five at Pryor (Santa Clara Creek), Huerfano, 24 May (Richard Taylor).

Painted Bunting: One female at Clear Springs Ranch, El Paso, 3 May (Steve Brown, m.ob.). Male and fe-male pair at Picture Canyon, Baca, 9 – 10 May (group led by William Kaempfer, m.ob.). One female at Brett Gray Ranch, Lincoln, 15 May (Brandon Percival). One male near Limon, Elbert, 11 May (David Sud-djian). Two males at Picture Canyon, Baca, 18 May (Steve Larson, Van Remsen, Steve Mlodinow). One male at Cottonwood Canyon, Baca, 18 May (Steve Mlodinow, Steve Larson). One female at Pueblo Res., Pueblo, 24 May (Brandon Percival).

Bobolink: Forty-eight in Cañon City, Fremont, 19 May (Rich Miller).

Rusty Blackbird: Two at Sand-stone Ranch, Weld, 1 Mar (Chris


Knight, Kathy Mihm Dunning). Forty-five near Longmont, Weld, 2 Mar (Steve Mlodinow). Four in Flor-ence, Fremont, 5 Mar (Rich Miller). Two at Brush SWA, Morgan, 14 Mar (David Dowell). One at Two Buttes SWA, Baca, 14 Mar (David Tønnes-sen, Mark Peterson, Glenn Walbek). As many as 5 at Chatfield SP (Douglas and Jefferson), 17 Mar – 8 Apr (Alec Hopping, m.ob.). One near Hasty, Bent, 31 Mar (Irene Fortune).

Baltimore Oriole: One in Pla-

cerville, San Miguel, 24 Apr – 1 May (Judy Kennedy, m.ob.) and 1 in Nu-cla, Montrose, 30 Apr – 1 May (Coen Dexter and Brenda Wright); rare in western Colorado.

PURPLE FINCH: One female in Las Animas, Bent, occasionally from 9 Jan – 6 Mar (Duane Nelson). One female northeast of Limon, Lincoln, 11 – 14 May (Glenn Walbek).

Brown-capped Rosy-Finch: A flock of 1,235 in Estes Park, Larimer, 9 May (Scott Rashid).

Worm-eating Warbler, Prewitt Res-ervoir, Washington County, 17 May 2015. Photo by David Dowell

Ovenbird, Skunk Canyon, Boulder County, 17 May 2015. Photo by Peter Burke

ACkNOwledgmeNTsContributions from the volunteer compilers are greatly appreciated: Jim Beatty (south-west), Coen Dexter (west), John Drummond (southeast), Forrest Luke (northwest), Brandon Percival, and David Silverman. Much of the information in this report was obtained from the eBird Basic Dataset from the Cornell Lab of Ornithology, Ithaca, New York.

David Dowell, [email protected]


CBRC REPORT

The 72nd Report of the Colorado Bird Records Committee Mark Peterson, Chair Colorado Birds Records Committee, and Bill Maynard, volunteer

IntroductionThis 72nd report of the Colorado Bird Records Committee (here-

after CBRC or Committee) presents the results of deliberations of the CBRC involving 276 reports submitted by 112 observers and documenting of 95 species from the period May 1979 to April 2015. Per CBRC bylaws, all accepted records received a final 7-0 or 6-1 vote to accept.

A backlog of accumulated records needs to be published before they become official, therefore only sightings of species representing first county records, taxa with very few Colorado records and reasons for a report not being accepted by the CBRC are detailed in this re-port. With this publication, Vaux’s Swift becomes Colorado’s 499th official bird species. All other records in this report are by necessity limited in details.

Committee members voting on these reports were John Drum-mond (Colorado Springs) Doug Faulkner (Arvada) Peter Gent (Boulder) Tony Leukering (Largo, Florida) Bill Maynard (Colorado Springs) Dan Maynard (Denver) Mark Peterson (Colorado Springs) Bill Schmoker (Longmont) and Glenn Walbek (Castle Rock).

The 71st report erroneously stated that the White Ibis (2013-182) observed in Alamosa, 28 July 2013, was a first for the San Luis Valley. It is not only the second for the San Luis Valley, but also the second for Alamosa. The first record is of one at Blanca Wetlands, 5 May 1998. We thank John Rawinski for bringing this error to our attention.

Committee NewsThe CBRC continues to recruit excellent members from the local

birding community.Mark Peterson is the new chairperson of the CBRC replacing Doug

Faulkner, Colorado Field Ornithologists’ newest president. Mark has extensive birding experience throughout the state. He has been bird-ing since five years of age―remembering singing Yellow-headed Black-birds (his current ringtone) and going to the Crane Festival at Monte Vista National Wildlife Refuge from his home in Waverly, Colorado. Mark is known as an excellent birder, the CFO County List Master, a past CFO board member and Convention Field Trip Coordinator.


Dan Maynard, replacing Mark Peterson on the CBRC, was born in Manitou Springs. He currently lives in Denver where he works on renewable energy projects as the Senior Ecologist for Core Con-sultants. When he isn’t speeding across Colorado in pursuit of a Big Year or Big Day, Dan can be found fly fishing, doing yoga or leading a technical rock climbing route on a pitch in Colorado or Utah.

Committee FunctionsThe Committee solicits documentation of reports in Colorado for

all species published in its Main Review List (coloradobirdrecords.org/ReviewList.aspx), species with no prior accepted record in Colo-rado and sightings of regularly occurring species that are considered out-of-range or out-of-season. Documentary materials should be sub-mitted online at the CBRC website (coloradobirdrecords.org). Al-ternatively, one can fill out the form printed on the dust jacket of this journal and mail it to the CBRC Chair, or request an electronic document from the Chair or Secretary (see this journal’s inside front cover for contact information).

Report FormatThe records in this report are arranged taxonomically following

the American Ornithologists’ Union (AOU) Check-list of North American Birds (AOU 1998) through the 56th Supplement (Chesser et al. 2015). We present the initials of the contributing observer(s), the official accession number and the vote tally in the first round and, if relevant, the second and third rounds (with the number of “accept” votes on the left side of the dash). The total number of state records is given in parentheses after the species scientific name.

The initial observer of the bird is underlined, if known, and is pre-sented first only if that person contributed documentation; additional contributors’ follow in alphabetical order by last name. If the initial observer is known with certainty, but did not submit documentation, those initials are underlined and presented last. Observers submitting a photograph or video capture are indicated with a dagger (†) and those who submitted a sketch by a lower-case, italicized “sk” (sk). In this report, county names are italicized. Abbreviations are used for the fol-lowing: reservoir (Res.) state park (SP) and state wildlife area (SWA).

ACCEPTED RECORDSWith the publication of this re-

port, Colorado’s state bird list stands at 499 species. Only Alaska, Arizona, California, Florida, New Mexico, Or-

egon, and Texas have more. The new-est addition to the state list is Vaux’s Swift – Chaetura vauxi (2015-46; 7-0) with a well-photographed individual reported by Brandon Percival west


of Cottonwood Picnic area along the Arkansas River, below Pueblo Reser-voir Dam, Pueblo on 28 April 2015. The CBRC bylaws section VIII C (10) states a first state record can be established by a single observer docu-mentation that includes photographic or audio-recorded evidence supportive of the identification. In this case the CBRC accepts the photographic evi-dence as supportive of the identifica-tion, thereby establishing it as the first state record.

Vaux’s Swift is named for William S. Vaux (1811–1882) a member of the Academy of Natural Sciences of Philadelphia and it was described by John K. Townsend in 1839 from specimens collected along the Colum-bia River. Vaux’s Swifts (C. v. vauxi) breed in northwestern U.S., Canada, and possibly in northeastern Mexico

(C. v. tamaulipensis). Small numbers of North American breeders winter in the U.S. from central California south and also in southeastern Louisi-ana and in northwest Florida (Birds of North America).

The Committee commented on the quality of the photographs, date of migration for this species compared with Chimney Swift (Chaetura pelagi-ca) and the details of the report sepa-rating it from Chimneys. Experts from outside Colorado were consulted, and they too validated this report as a Vaux’s Swift. Tom Johnson’s thorough analysis of these two Chaetura swifts, including a “modified aspect ratio” ap-proach and nine characters to look for in separating these two species, occurs in the print version of the September/October 2013 Birding, pp. 48-52.

Brant – B. b. nigricans. (JTh†,

eBird data showing migrant Vaux’s Swift wintering records from southeastern U.S. and from various locations in western New Mexico, Nevada, and Utah, in addition to western breeding areas. Image provided by eBird (www.ebird.org) 10 August 2015.


DD†, EL†, SGM; 2012-207; 7-0) Loveland area, Larimer, 3-18 Decem-ber 2012; (SGM; 2013-13; 7-0) Jack-son Lake, Morgan, 23 December 2012; (NM†; 2013-16; 7-0) providing a first for Otero found during the Rocky Ford CBC at Lake Cheraw, 15 December 2011; (RBe†; 2014-4; 7-0) Larimer, Prospect Ponds Natural Area, 31 De-cember 2013.

Brant – Branta bernicla. The fol-lowing three documented Brant were all unanimously accepted as Brant but not to any specific taxon. They came from Redstone Park and Chat-field State Park, Douglas, Greeley, Weld and Equalizer Lake and Houts Reservoir, Larimer. (EDo†, JH†, BM†, CN†, KPe†, TR†, CW†, SS; 2013-290; 7-0) 15 December 2013 to 19 February 2014; (SGM; SW; 2014-12; 7-0) 15 January 2014; (SB†, SGM†; 2014-20; 7-0) 25 October 2013 to 11 November 2013.

Trumpeter Swan – Cygnus bucci-nator (BS†, NL; 2013-47; 6-1) McKay Lake, Adams, 13-19 January 2002.

Eurasian Wigeon – Anas penelope (RBr; 2012-197; 7-0) Colorado River, Mesa, 15 March 2010; (JD†, BKP†, RMi†, DM; 2012-214; 7-0) Willow and Ash St. 16 and 23 December 2011 thru 1 January 2012 at Centen-nial Park, Fremont; (SGM†; 2013-256; 7-0) Weld, 20 March 2013; (JTr†; 2013-260; 7-0) Riverfront trail at 29 Road, Mesa, 27 April 2013; (HK†, KPe†; 2014-41; 7-0) Walker Pit, Douglas, 15-16 March 2014.

Long-tailed Duck – Clangula hy-emalis (BKP†, SM; 2013-104; 7-0) Brush Hollow Reservoir, Fremont, 20 January 2012.

Red-necked Grebe – Podiceps grise-gena (LF†, CH†; 2013-181; 7-0) Lake John, Jackson, 10-14 July 2013.

Neotropic Cormorant – Phala-crocorax brasilianus (RHi†; 2013-112; 7-0) Valco Ponds SWA, Pueblo, 5 April 2013; (SGM; 2013-130; 7-0) Stewarts Pond on WCR 46, Weld, 14 April 2013; (SGM†; 2013-159; 7-0) Weld County Road 7 entry road to St Vrain State Park, Weld, 15 May 2013.

Least Bittern – Ixobrychus exilis (RMi; 2012-203; 7-0) Holcim Wet-lands, Fremont. 25 July 2012; (BKm; 2013-165; 7-0) NE pond of Sawhill Ponds complex, Boulder, 13 June 2013.

Tricolored Heron – Egretta tricolor (JD†, BKP†, SGM†, SM; 2013-167; 7-0) Holcim Wetlands, Fremont 14 June 2013 to 3 July 2013; (JD†, BM†; 2013-171; 7-0) Lake Hasty, Bent, 22 June 2013.

Reddish Egret – Egretta rufescens (DD†, DN; 2013-265; 7-0) Lake Mer-edith, Crowley, 13 July 2013; (JSt†; 2014-38; 7-0) John Martin Reservoir State Park, Bent; 20-22 August 2013.

Cattle Egret – Bubulcus ibis (BBa†; 2013-245; 7-0) Pagosa Springs, Archu-leta, 1 November 2013.

Yellow-crowned Night-Heron – Nyctanassa violacea (LH†; 2010-183; 6-1) Larimer, 5 September 2005; (HK†; 2013-110; 6-1) Chatfield State Park, Jefferson, 19 May 1979; (DD†, JD†, BM†, BP†, RT, KL; 2013-222; 7-0) Birdsall Road, El Paso, 5-13 Oc-tober 2013; (WG, BM†; 2014-24; 7-0) Carp Lake, El Paso, 26-27 August 2005.

Common Black Hawk – Buteogal-lus anthracinus (JBs; 2013-249; 7-0) Hotchkiss, Delta, 5 April 2013.


Black Rail – Laterallus jamaicensis (MP; 2013-229; 7-0) Holcim Wet-lands, Fremont, 15 June 2013.

Whimbrel – Numenius phaeopus (MH; 2013-252; 7-0) Fruitgrowers Reservoir, Delta, 20 May 2000.

Hudsonian Godwit – Limosa hae-mastica (DD†, GP; 2014-37; 7-0) Bee-be Draw, Weld, 21-23 May 2013.

Buff-breasted Sandpiper – Calid-ris subruficollis (DD†; 2014-18; 7-0) Jackson Reservoir, Morgan, 21 August 2013.

American Woodcock – Scolopax minor (DG†; 2013-282; 7-0) specimen recovered at UCC Campus, El Paso, 9 February 2013; (CT†, BM†, BKP†; 2014-21; 7-0) Fountain Creek, El Paso, 9 February 2014; (KPa†; 2014-31; 7-0) Fountain Creek Regional Park, El Paso, 15 January 2013.

Red Phalarope – Phalaropus fuli-carius (CDe†; 2013-101; 7-0) Ridgway Reservoir, Ouray, 20 August 2012.

Pomarine Jaeger – Stercorarius po-marinus (EDe†, JD†, BM†; 2013-169; 7-0) Antero Reservoir, Park, 11-17 June 2013; (GW†, KPe†; 2014-27; 7-0) Chatfield State Park, Douglas and Jefferson, 16-26 October 2013; (DN†; 2014-39; 7-0) Blue Lake (Adobe Creek Reservoir) Kiowa, 18 June 2013.

Parasitic Jaeger – Stercorarius para-siticus (GK, GW†, DN; 2014-28; 7-0) Blue Lake (Adobe Creek Reservoir) Bent and Kiowa, 4-9 November 2013.

Black-legged Kittiwake – Rissa tri-dactyla (MH†; 2013-262; 7-0) High-line Lake State Park, Mesa, 19-20 No-vember 2013.

Sabine’s Gull – Xema sabini (TLe†; 2014-14; 7-0) Eleven Mile State Park, Park, 29 October 2005.

Little Gull – Hydrocoloeus minutus (NK†, SW; 2012-200; 7-0) Wind-sor Lake, Weld, 2 December 2012; (MO, CT; 2013-109; 7-0) Lake Mer-edith, Crowley, 7 April 2013; (BM†, BKP†, RMo; 2013-220; 7-0) Pueblo Reservoir, Pueblo, 4-9 October 2013; (SGM, PG, NK†; 2013-243; 7-0) Ter-ry Lake and Clark Reservoir, Boulder, 30 October thru 3 November 2013.

Mew Gull – Larus canus (TLe†, LK; 2014-19; 7-0) Cherry Creek State Park, Arapahoe, 27 September 2008.

Western Gull (4)– Larus occiden-talis (SGM; 2013-239; 7-0) A well described but un-photographed adult dark-mantled gull found at Timnath Reservoir, Larimer, 5 October 2013 was compared with Herring, Lesser Black-backed and California Gulls. Committee members felt that all es-sential and secondary features were noted to separate congeners.

Iceland Gull – Larus glaucoides (JVv, TLe; 2002-75; 7-0) Erie landfill north of Hwy 7, Prince Lakes, Erie and Thomas Reservoirs, Boulder, 9-18 April 2000; (DD†, NL, GW†; 2013-43; 7-0) Teller Lake No. 5 and Culver Ponds, Boulder, 1-2 February 2013; (BKP†; 2013-61; 7-0) Pueblo Reservoir, Pueb-lo, 3 January 2013; (LMa†; 2013-93; 6-1) Anthem Pond, Broomfield, 26 January 2013; (SGM†; 2013-124; 6-1) Stewarts Pond, Weld, 31 March 2013; (SGM; 2013-126; 7-0) Black Hollow Reservoir, Weld, 3 April 2013; (NK; 2014-5; 7-0) Lake Loveland, Larimer, 30 December thru 2 January 2014; (SGM†; 2014-36; 7-0) Woods Lake, Weld, 19 February 2014; (DD†, SGM; 2014-42; 7-0) Aurora Reservoir, Arap-ahoe, 19-29 January 2014.


Slaty-backed Gull (2) – Larus schistisagus (DD†, SGM†, KPe†; 2014-8; 7-0) Aurora Reservoir Arap-ahoe hosted an adult Slaty-backed Gull 15 December 2013 through 3 January 2014. Although the winter-ing gull showed an un-streaked white head, it also showed the characteristic “string of pearls,” the bold pattern of white mirrors and tongue tips seen on the dorsal and ventral surfaces of the outer primaries in flight, broad white trailing edge to the secondaries (skirt) dark slate-gray mantle, broad white scapular and tertial crescents and bright pink legs and feet, all charac-teristics of this very rare visitor from Asia. Comparison with a look-alike “Vega Gull”, was noted (longer wings, thinner bill, lighter gray mantle, no-ticeable contrast between black wing-tips and upperparts) eliminating that taxon. Distant, but distinct photo-graphs on different dates were key for this second Colorado and first county record.

Herring Gull x Glaucous-winged Gull – (DD†; 2013-51; 7-0) Herring Gull (Larus argentatus) and Glaucous-winged Gull (Larus glaucescens) regu-larly interbreed in southwest Alaska and their hybrids increasingly occur along the North American Pacific Coast south to California (Howell and Dunn. 2007). An apparent first year hybrid was well photographed from Teller Lake No. 5, Boulder, 24 Janu-ary 2014. The identification indica-tors given in the report specify promi-nent wing patterning and patches of a lighter color on a mostly-black bill resembling a dark Glaucous-winged Gull or a washed out Herring Gull.

The observer thought this bird, based on detailed photographic comparison, was the same gull reported from Pueb-lo Reservoir, Pueblo on 29 December 2012.

Glaucous-winged Gull – Larus glaucescens (SGM; 2013-35; 6-1) Pueblo Reservoir, Pueblo, 1 January 2013; (SGM, TLe; 2013-77; 7-0) Val-mont Reservoir, Boulder, 27 January 2013; (DD†; 2013-264; 7-0) Neegron-da Reservoir, Kiowa, 10 August 2013; (SGM; 2013-267; 7-0) Windsor Res-ervoir, Weld, 13 November 2013; (SGM; 2013-268; 7-0) Aurora Res-ervoir, Arapahoe, 24 November 2013; (SGM†; 2013-280; 7-0) Pueblo Res-ervoir, Pueblo, 11-12 December 2013; (SGM†; 2014-10; 7-0) Aurora Reser-voir, Arapahoe, 3 January 2014; (BKP; 2014-29; 7-0) Pueblo Reservoir, Pueb-lo, 15 February 2014.

Great Black-backed Gull – Larus marinus (CM†; 2013-108; 6-1) Cher-ry Creek State Park, Arapahoe, 23 January 2011; (NK†; 2013-261; 7-0) Horseshoe Lake, Larimer, 17 April 2013.

Arctic Tern – Sterna paradisaea (GW†, DD; 2013-213; 7-0) Cherry Creek State Park, Arapahoe, 23 Sep-tember 2013; (SGM; 2013-217; 7-0) Terry Lake and Clark Reservoir, Boul-der, 29 September 2013.

Inca Dove – Columbina inca (BKP†; 2006-190; 7-0) Rocky Ford, Otero, 16 April 2005; (CA; 2013-37; 6-1) Cottonwood Canyon, Baca, 17 May 2012; (JSt†; 2014-16; 7-0) Farm-yard, Prowers, 14 October 2005.

Black-billed Cuckoo – Coccyzus erythropthalmus (JBr†; 2013-209; 7-0) this first for Adams County was found


at Barr Lake State Park, 14 September 2013.

Snowy Owl – Bubo scandiacus (KMD, JK†; 2014-32; 7-0) HWY 94 and LCR 11, Lincoln, 26 January 2014.

Boreal Owl – Aegolius funereus (DJ, TM†; 2013-72; 7-0) southeast of Silverton, San Juan, 16 July 2009.

Lesser Nighthawk – Chordeiles acutipennis (SGM; 2013-178; 7-0) Adobe Creek Reservoir, Kiowa, 22 June 2013.

Magnificent Hummingbird – Eu-genes fulgens (MB; 2012-153; 7-0) for the third year in a row this bird was found at Tunnel Campground, Lar-imer, 16 July 2012.

Ruby-throated Hummingbird – Archilochus colubris (SW†, NK†; 2012-181; 7-0) Walters residence, south Loveland, Larimer, 12-13 September 2012; (MM; 2013-139; 6-1) South Mesa Trail, Boulder, 13 May 2013; (DS; 2013-202; 7-0) Colorado City and Rye, Pueblo, 1 September 2013; (JSt†; 2013-225; 7-0) Farmyard, Prow-ers, 28-29 September 2013; (RHo†; 2013-231; 7-0) Long Pond, Larimer, 18-21 September 2013; (LP†; 2014-1; 7-0) a first for Alamosa county was found at the Medano-Zapata Ranch, 13 September 2013; (MC†; 2014-30; 7-0) Lakewood, Jefferson, 3-4 Octo-ber 2013; (DD; 2014-34; 7-0) Lamar, Prowers, 2 October 2013.

Anna’s Hummingbird – Calypte anna (DS; 2013-201; 7-0) Colorado City and Rye, Pueblo, 9 September 2013; (RBr; 2013-281; 6-1) Grand Junction, Mesa, 4-19 December 2004.

Costa’s Hummingbird – Calypte costae (BM†, BP†; 2013-273; 7-0) this first for El Paso County had a long

stay at an estate in Colorado Springs, 1 November 2013 thru 26 February 2014. The estate’s caretakers, provid-ing the bird flowering plants along with a protein supplement, were able to watch the male hummingbird molt its gorget feathers and by the end of the period the bird was frequently seen in a territorial display (Colorado Birds. Vol. 48. No. 3).

Acorn Woodpecker – Melanerpes formicivorus (MW†, PB†, JD†, NK†, TLe†, BM†, KMD†, NM†, SP; 2012-211; 7-0) Willow Circle, El Paso, 15 December 2012 thru 18 April 2013; (HK†, KD; 2013-244; 7-0) provid-ing for a first for Douglas, this Acorn Woodpecker was found by Kathy and Howard Dressel on 24 May 2013.

Red-bellied Woodpecker – Mel-anerpes carolinus (SGM†; 2011-198; 7-0) Crow Valley Campground, Weld, 1 October 2011; (PWN†; 2014-3; 7-0) providing a first for Huerfano county, Polly Wren Neldner found a Red-bellied Woodpecker in her yard which stay from 17 November 2004 thru 10 February 2005.

Yellow-bellied Sapsucker – Sphy-rapicus varius (LA†; 2013-83; 7-0) Redlands area, Mesa, 6 February 2013.

Eastern Wood-Pewee – Contopus virens (SGM†; 2013-155; 7-0) Jules-burg, Sedgwick, 26 May 2013.

Yellow-bellied Flycatcher – Em-pidonax flaviventris (DLe†; 2013-251; 6-1) overlooked or difficult to iden-tify, only the ninth Colorado record and first Prowers county record was recorded in Lamar on 15 September 2013. This small Empidonax flycatcher breeds in coniferous forests and bogs across Canada and into Alaska win-


tering from northeastern Mexico south to western Panama. Excellent photographic evidence supported the bird having a complete eye ring, big head and a slightly larger version of a Least Flycatcher but with a longer pri-mary projection and blackish wings. The one member voting not to ac-cept the record thought the eye ring should be wider for this species and he mentioned the primary project on the well-photographed bird was too short for a Yellow-bellied Flycatcher.

Alder Flycatcher – Empidonax alnorum (DF†; 2013-55; 7-0) Barr Lake SP, Adams, 1 September 2012; (SGM†; 2013-189; 7-0) Last Chance, Washington, 11 August 2013.

Least Flycatcher – Empidonax min-imus (PD; 2013-250; 7-0) Connected Lakes, Mesa, 26 May 2007.

Hammond’s Flycatcher – Empi-donax hammondii (BM†, BKP†, DM; 2013-34; 7-0) On the 113th Christ-mas Bird Count, in particular the annual Penrose CBC on 16 Decem-ber 2012, Dan Maynard detected an Empidonax flycatcher where a spring begins its descent into a wooded ra-vine on a Willow Street dairy farm in Cañon City, Fremont county. The bird was seen by many, photographed, and documented. It remained for six days, becoming the first Empidonax fly-catcher documented in December in Colorado.

Gray Flycatcher – Empidonax wrightii (SGM†; 2011-195; 7-0) Crow Valley Campground, Weld, 20 Au-gust 2011; (SGM†; 2011-196; 7-0) Thompson Ranch, Lincoln, 5 Septem-ber 2011.

Black Phoebe – Sayornis nigricans

(BU†; 2012-201; 7-0) Rio Grande State Wildlife Area, a first for Rio Grande, 19 July 2012; (DA†; 2013-75; 7-0) Florence River Walk, Fremont, 15 June 2013; (BJ†; 2013-106; 7-0) La Veta, Huerfano, 9 September 2012.

Great Crested Flycatcher – Myiar-chus crinitus (SGM†; 2011-197; 7-0) Thompson Ranch (private) Lincoln, 5 September 2011.

Brown-crested Flycatcher – My-iarchus tyrannulus (LP†; 2014-2; 7-0) was found by visiting British birder, Laurence Pitcher on the Medano-Za-pata Ranch in the San Luis Valley Al-amosa on 29 June 2013. Only present for one day, it will become only the second state and first county record. Photographs and a written description nicely separated it from its congeners, in particular Ash-throated (M. cinera-scens) and Great Crested (M. crintus) flycatchers. Experts living in Brown-crested’s U.S. range, southeastern California, extreme southern Utah and Nevada, southeastern Arizona, southwestern New Mexico, and south Texas were consulted. This southern species is a resident in parts of Mexico, Central America, and in South Amer-ica. In South America it breeds mostly east of the Andes south to southern Brazil, Paraguay, and northern Argen-tina (Cardiff and Dittmann, 2000).

Eastern Kingbird – Tyrannus tyran-nus (JD; 2013-170; 7-0) Antero Reser-voir, Park, 17 June 2013.

Scissor-tailed Flycatcher – Tyran-nus forficatus (DB; 2013-26; 7-0) just east of the Cottonwood Canyon pic-nic area and campground, Las Animas, 1 June 1996.

Pacific Wren – Troglodytes pacificus


(GW; 2014-26; 7-0) this provides a first county record that was found at the private Thompson Ranch, Lincoln County.

Winter Wren – Troglodytes hiemalis (KMD; 2012-79; 7-0) trail to Black Lake in Rocky Mountain National Park (Glacier Gorge Trailhead) Lar-imer, a rare summer record from 2 July 2012; (CL†; 2013-19; 7-0) Durango, La Plata, 24 December 2012.

Sedge Wren – Cistothorus platensis (SGM; 2012-191; 7-0) Kinny SWA, Lincoln, 21 October 2012; (NM†; 2013-14; 7-0) Walden Ponds, Boulder, 17 November 2011; (SGM; 2013-240; 7-0) TNC Fox Ranch (private) Yuma, 12 October 2013; (BBi†; 2013-241; 7-0) Spring Creek Trail, Larimer, 24 October 2013; (DD†; 2014-15; 7-0) Prewitt Reservoir, Logan, 16 Novem-ber 2013.

Gray-cheeked Thrush – Catharus minimus (NG†; 2014-17; 7-0) Chico Basin Ranch, El Paso, 13 May 2013; (NG†; 2014-22; 7-0) Chico Basin Ranch, El Paso, 10 May 2013; (NG†; 2014-23; 7-0) Chico Basin Ranch, El Paso, 16 May 2013.

Varied Thrush – Ixoreus naevius (BKP; 2013-117; 7-0) Walsenburg, providing a first for Huerfano, 1 April 2000; (BKP†, PWN†; 2014-11; 7-0) La Veta, Huerfano, 12-30 January 2014.

McCown’s Longspur – Rhyncho-phanes mccownii (TLi, CDo; 2013-118; 7-0) 4 miles west of Steamboat Springs, Routt, 18-19 April 2013.

Worm-eating Warbler – Helmithe-ros vermivorum (CDe†; 2014-7; 7-0) Grand Junction, Mesa, 28-29 Novem-ber 2013.

Golden-winged Warbler – Vermi-vora chrysoptera (TLe; 2013-278; 6-1) Barr Lake State Park, Adams,

Prothonotary Warbler – Proto-notaria citrea (TM†; 2012-187; 7-0) found by Robin and Kendall Henry in Glenwood Springs on 9 September 2012, was a first for Garfield county; (SA; 2013-214; 7-0) Pastorius State Wildlife Area, La Plata, 9 September 2013.

Tennessee Warbler – Oreothlypis peregrina (BP†; 2013-271; 7-0) Pueblo City Park, Pueblo, this bird found in November stayed until at least 1 De-cember 2013 to provide a first winter record for Colorado.

Connecticut Warbler – Oporor-nis agilis (NG†; 2013-29; 7-0) Chico Basin Ranch, El Paso, 10 September 2012; (SGM, GW; 2013-195; 7-0) Prewitt Reservoir State Wildlife Area, Washington, 2 September 2013.

Mourning Warbler – Geothlypis Philadelphia (BKP†; 2013-145; 7-0) Brett Gray Ranch (private) Lincoln, 18 May 2013; (SGM; 2013-204; 7-0) Flagler Reservoir State Wildlife Area, Kit Carson, 11 September 2013; (NK†, KK, JSh; 2013-207; 7-0) Fort Col-lins, Larimer, 9-10 September 2013; (MM; 2013-208; 7-0) Walden Ponds/Sawhill Ponds Complex, Boulder, 11 September 2013; (SGM†; 2013-212; 7-0) Jackson Reservoir, Morgan, 2 September 2013.

Kentucky Warbler – Geothlypis formosa (TLe†; 2012-196; 7-0) Pritch-ett, Baca, 31 May 2011.

Cape May Warbler – Setophaga tigrina (AS†; 2012-186; 7-0) Kiowa Creek Sanctuary, El Paso, 2 October 2012; (BKP†, RO†, GW†; 2013-138;


7-0) Two Buttes State Wildlife Area, Baca, 10-11 May 2013; (BKP†; 2013-149; 7-0) Chico Basin Ranch, Pueblo, 22 May 2013; (BKP†, JD†, SGM†; 2013-152; 7-0) Chico Basin Ranch, Pueblo, 22-24 May 2013; (GW†; 2013-196; 7-0) South Republican SWA, Yuma, 21 May 2013; (DLe†; 2013-257; 7-0) Grandview Cemetery, Larimer, 7-8 October 2013.

Northern Parula – Setophaga amer-icana (BKP†; 2013-74; 7-0) Pueblo City Park, Pueblo, 5 December 2012.

Bay-breasted Warbler – Setophaga castanea (DLe†; 2013-258; 7-0) Boul-der, Boulder, this bird was around for approximately three weeks but only documented for 9 November 2013.

Blackburnian Warbler – Setophaga fusca (HK; 2013-276; 7-0) Chatfield State Park, Jefferson, 7 October 1987.

Chestnut-sided Warbler – Setoph-aga pensylvanica (JBe†; 2012-180; 7-0) Navajo Reservoir, Archuleta, 2 Octo-ber 2012.

Yellow-throated Warbler – Setoph-aga dominica (BKP†; 2013-73; 7-0) Pueblo City Park, Pueblo, this long staying bird showed up in Septem-ber and was last seen on 8 December 2012.

Prairie Warbler – Setophaga dis-color (BKP, MP; 2013-114; 7-0) Lake DeWeese, Custer, 21 September 2004; (BKP, DS; 2013-115; 7-0) Diversion Gate near Colorado City, Pueblo, 8 May 2003.

Hermit Warbler – Setophaga occi-dentalis (BKP; 2013-113; 7-0) Upper Queens Reservoir, Kiowa, 6 May 2001.

Canada Warbler – Cardellina ca-nadensis (DR; 2013-95; 6-1) Lamar Community College, Prowers, 7 Octo-

ber 2011; (BKP; 2013-224; 7-0) Pueb-lo Reservoir area, Pueblo, 7 September 2013; (DLe†; 2013-253; 7-0) Lamar, Prowers, 16 September 2013.

Eastern Towhee – Pipilo eryth-rophthalmus (SGM; 2012-198; 6-1) Tamarack Ranch SWA, Logan, 2 June 2011; (DD†; 2012-216; 6-1) Tama-rack Ranch SWA, Logan, 7 July 2012; (BKP†; 2013-2; 7-0) Greenwood, Custer, 1 January 2013, although not documented this bird was seen into April of 2013; (SGM; 2013-154; 7-0) Tamarack Ranch SWA, Logan, 26 May 2013; (RR; 2013-283; 6-1) east of I76 on 160th just east of the railroad tracks, Adams, 4-31 January 2013.

Field Sparrow – Spizella pusilla (SGM; 2011-194; 7-0) Black Hollow Reservoir, Weld, 5 May 2001; (JD; 2013-30; 7-0) Chico Basin Ranch, El Paso, 5 October 2012; (BKP; 2013-223; 7-0) Chico Basin Ranch, Pueblo, 28 September 2013.

White-throated Sparrow – Zono-trichia albicollis (TLe†, SGM; 2013-50; 7-0) Moose Visitor Center, Jackson, 26 January 2013. A nice high elevation record for this species in Colorado. There was also one at this location the previous year but not documented.

Hepatic Tanager – Piranga flava (SO; 2013-254; 7-0) 5 miles south of Tobe, Las Animas, 14 May 2004.

Scarlet Tanager – Piranga olivacea (SW; 2012-193; 7-0) Loveland, Lar-imer, 9 September 2012; (DE; 2013-263; 6-1) McKay Lake, Adams, 5 May 2005; (RS; 2013-277; 7-0) Chautau-qua Cabins, Boulder, 18 February 1994.

Eastern Meadowlark – Sturnella magna (BKm; 2013-164; 6-1) Beech Open Space, Boulder, 13 June 2013.


Baltimore Oriole – Icterus galbula (TM; 2014-33; 7-0) providing a first for Garfield County, this Baltimore Oriole was found by Robin and Ken-dall Henry in Glenwood Springs on 15-16 May 2013.

Purple Finch – Haemorhous purpu-reus (SGM; 2012-188; 6-1) Holyoke, Phillips, 30 September 2012; (GW†; 2013-96; 7-0) Castle Rock, Douglas, 25 December 2012 thru 15 March 2013; (MP†; 2013-232; 7-0) Flagler Reservoir State Wildlife Area, Kit Carson, 13 October 2013.

RECORDS NOT ACCEPTEDEvery Colorado birder, beginner

and expert alike, will sooner or later have a bird report “not accepted” by the CBRC. While some written de-scriptions may describe a look-alike species or subspecies causing the non-acceptance, more often than not, unaccepted reports simply do not provide enough descriptive details or convincing photographs to provide “without a doubt” evidence to support a record. Or, the key call or song was not heard well or not described well or at all. Even a 5-2 majority vote in favor of a record being accepted does not meet the required 6-1 or 7-0. The bird may, in fact refer to the species reported, but the details provided may have been not convincing enough. Do not be insulted. Next time, detail every key identification point you ob-served (but not a word-for-word field guide description). Separate all of the look-alike species and when appropri-ate address potential hybrids. When photographing, attempt to get clear shots that show key features/behavior/

posture or include a sound recording or a sonogram when possible.

Mute Swan – Cygnus olor. In spite of almost yearly sightings of Mute Swan in Colorado, there have been no records of the species accepted and it currently does not appear on the Col-orado Bird Checklist. There is no cur-rently accepted method to determine if Colorado Mute Swans escaped from captivity or if they wandered to Colo-rado on their own. For example, what is the provenance of the Mute Swan west of Boulder Creek in Weld on 27 October 2013? The reported bird was an obvious Mute Swan, but one of un-known origin (2013-238; 3-4).

Trumpeter Swan – Cygnus buccina-tors. Lack of a detailed description or photographs separating this from the smaller Tundra Swan (Cygnus colum-bianus) persuaded a majority of CBRC members to not accept this 15 No-vember 2012 report (2012-185; 3-4) from North Delaney Lake, Jackson.

Glossy Ibis – Plegadis falcinellus. A Plegadis ibis seen on 18 April 2004 at 20 Mile Road, Routt was not accept-ed by Committee members primarily because the bird was not in full alter-nate plumage and four of the mem-bers commented that the report did not rule out a hybrid (2013-248; 3-4). Hybrid White-faced Ibis x Glossy Ibis, depicted and described as “intermedi-ate” by Sibley (2014) are increasingly reported from Colorado (see Leuker-ing 2008). One reviewer mentioned that size is not a consistent character for separating the two species.

Swallow-tailed Kite – Elanoides forficatus. An observer driving north on I-25 in Larimer on 3 April 2013


was unable to present convincing details of the raptor he thought was this species. The driving speed, 75 mph, was felt as giving the observer too little time to sufficiently identify such a rarity; Colorado has only five accepted records (2013-99; 0-7) the last in 1993.

Harris’s Hawk – Parabuteo unicinc-tus. A dark raptor was described from near Holly Municipal Airport, Prow-ers on 22 April 2012. Three rounds of voting did not provide the margin needed for acceptance. Negative vote comments suggested a reported band on the tail was not visible in the sub-mitted photographs (2013-65; 4-3; 4-3; 5-2). One review agreed with the I.D. but was not okay with the bird’s provenance, due to the extensive use of Harris’s Hawks by falconers (pos-sible escaped bird). One reviewer suggested the reported raptor might be a dark-morph Ferruginous Hawk whereas another reviewer, one who voted in favor of acceptance, men-tioned Harris’s Hawk was the only Colorado raptor showing the chestnut shoulder patches seen in the submit-ted photographs. Also mentioned as a plus in favor or acceptance were vis-ible tarsi feathered halfway, a good character for Harris’s Hawk. Another reviewer liked the amount of yellow on the bird’s cere for Harris’s Hawk. A raptor seen on 10 October 2013 at Crown Hill Park/Lake/Cemetery, Jef-ferson was observed without binocu-lars (2013-230; 0-7). All Committee members mentioned a lack of details in the report and questioned whether the bird’s identification. Due to the popularity of the species with falcon-

ers, reports to records committees of Harris’s Hawks require extra scrutiny and observers should look for bands and/or jesses and should state such in their submitted details. This aspect was noted by many reviewers for both of these reports.

Western Gull – Larus occidenta-lis. A dark-mantled gull fitting the description of Western Gull was re-ported from Totten Reservoir, Mont-ezuma on 22 April 2012. During the second round of voting (2012-64; 5-2; 2-5) Committee members decided a hybrid could not be completely ruled out based on a series of photographs showing mantle coloration a bit light-er than expected and with leg and feet color not perfectly matching either of the two Pacific Coast subspecies of Western Gull.

Herring (Vega) Gull – Larus ar-gentatus vegae. Though still considered a subspecies of Herring Gull by the AOU Check-list Committee (Chess-er et al. 2015) the eastern Siberian form known as Vega Gull is regular in western Alaska, but with only a few accepted records from farther south on the U. S. coast. Adults are slightly darker-mantled in adult plumages than is the typical ABA-area form (smithsonianus) and have brighter pink legs and dark eyes. A gull at Lake Loveland, Larimer on 28 December 2011 was thought by CBRC members to be inseparable from the highly vari-able plumage of Herring Gulls win-tering in Colorado (2012-209; 1-6). Another individual was reported from Lake Loveland, Larimer on 17 Decem-ber 2012. The bird exhibited large scapular and tertial crescents and ex-


tensive neck streaking, but the report was not accepted by the Committee because photographs were thought to be inconclusive (2012-210; 0-7).

Ruby-throated Hummingbird – Archilocus colubris. Only two species of Archilochus hummingbird exist in the world. With a good view and/or upon examination of photographs show-ing a profile view of the folded wings, identification to genus is straightfor-ward, with the noticeable difference in width between the narrow inner primaries and the broad outer pri-maries being definitive. Separating Ruby-throated from Black-chinned Hummingbird (A. alexandri) however, is more difficult, and the shape of the tip of the outermost primary is an im-portant separator, particularly in fe-males and many immature males. The committee here provides details on four reports that were found at least somewhat lacking. The Committee commented that the presented evi-dence for a hummingbird in southern Prowers on 5 September 2013 was in-sufficient to eliminate Black-chinned Hummingbird (2013-187; 5-2, 1-6). The primary tips were not described sufficiently, although most Committee members believed the report pointed toward Ruby-throated Humming-bird. Committee members expressed concern about insufficient details in the report one noted 25 July 2013 at Lakewood, Jefferson. (2013-194; 3-4) and four voters thought the lack of a “wing whirr” did not sufficiently rule out Black-chinned Hummingbird. Details of another, reported from Es-tes Park, Larimer on 29 August 2013, were sufficient to differentiate it from

other hummingbird species except Black-chinned (2013-233; 4-3; 0-7). Neither the photographs nor a de-tailed description could eliminate Black-chinned Hummingbird for a majority of Committee members con-cerning a report from Spring Creek Trail, Larimer on 21 September 2013 (2013-274; 3-4).

Yellow-bellied Sapsucker – Sphy-rapicus varius. A 19 February 2005 sapsucker report from Pueblo City Park, Pueblo required two rounds of voting (2005-13; 5-2; 3-4) for a deci-sion to be reached. Two voters men-tioned that the lack of a red nape does not necessarily eliminate Red-naped Sapsucker. Observers should focus on more than just the presence or absence of a red nape patch, particularly the back pattern and the precise details of red, black, and white on the throat. Additionally, some members noted that Yellow-bellied x Red-naped Sap-sucker, a regular hybrid combination, was not addressed.

Coastal Pacific Group Downy Woodpecker – Picoides pubescens gairdnerii. Spots on the upper breast, not streaks was indicative of a Downy Woodpecker seen at Ish Reservoir, Boulder on 20 October 2012, but some members felt intergrades with Rocky Mountain subspecies of Downy Woodpecker could not be ruled out. Other voters wanted more informa-tion on patterns of vagrancy in Pacific Downies before adding this north-western subspecies group to the offi-cial Colorado list (2012-190; 3-4).

Eastern Wood-Pewee – Contopus virens. An old record from 27 May 2009 was evaluated. Photographs of a


silent wood-pewee in Pueblo were not enough to convince two Committee members to accept this report after three rounds of voting (2009-120; 5-2; 5-2; 5-2). Eastern Wood-Pewee usually has less dark tip on its orange bill than Western, more of a greenish cast to upperparts or breast, and the greater coverts are usually broader, but these are all subtle secondary charac-ters with some overlap found in mu-seum specimens. Reviewers were re-luctant to accept a report of another silent wood-pewee, from Lake Beck-with Dam, Pueblo on 27 May 2013 (2013-153; 2-5). Some comments mentioned that the observer did not see enough of the bird’s plumage and that the observation was of short du-ration. See Lee et al. (2008) for a very good article dealing with the separa-tion of wood-pewee species.

Alder Flycatcher – Empidonax alnorum. A 22 July 2012 Empidonax flycatcher from Kinney SWA Lincoln did not receive the necessary votes by the Committee for acceptance. The “no” vote comments (2012-87; 4-3; 3-4) mention the early date for this normally late migrant and the diffi-culty in positively separating Alders from the eastern subspecies of Willow Flycatcher (Empidonax trailii trailii) in some circumstances. Another Com-mittee member thought hearing only one note was insufficient for conclu-sive evidence supporting the reported identification.

Scissor-tailed Flycatcher – Tyran-nus forficatus. The Road 18 overlook at John Martin Reservoir, Bent was the spot where a Scissor-tailed Flycatcher was reported on 29 July 2012. The

report had some conflicting details about the belly color and the length of the tail streamers, enough to leave some doubt in the mind of four Com-mittee members (2013-98; 3-4).

Chihuahuan Raven – Corvus cryp-toleucus. Perhaps the most difficult field-identification problem in Colo-rado is separating Chihuahuan Raven from Common Raven (C. corax). An out-of-range bird at Longmont, Boul-der, on 13 December 2012 was unani-mously thought to be insufficiently separated from the more expected Common Raven (2012-205; 0-7). The description was of just the call notes. Another report originated from the Big Thompson River Walk, Larimer, on 20 April 2013. Some reviewers commented on the lack of details in the description of the raven’s tail, the lack of a detailed analysis of the call notes, and the northern Colorado lo-cation of this southern species. Others commented on the general difficulty of differentiating the two Colorado ra-ven species. Pieplow (2014) discusses raven vocalizations, while Leukering (2015a) discusses visual identification elsewhere in this issue.

Pacific Wren – Troglodytes pacifi-cus. The subspecies of Pacific Wren most likely to occur in Colorado, T. p. salebrosus, is not generally depicted well in field guides and, in many re-spects, is quite similar in appearance to Winter Wren (Leukering 2010) thus it causes confusion here. The re-port of a dark, stub-tailed wren from Fox Ranch, Yuma, on 6 October 2012 was not accepted, mostly because the report lacked a good photograph and, apparently, no sound recording


was made, though double-noted calls were described as being similar to a Wilson’s Warbler’s call (2012-136; 4-3; 3-4). See Leukering (2010) and Faulkner (2012) for more discussion on differences and references.

Winter Wren – Troglodytes hiemelis. On 19 May 2013, a likely stub-tailed wren was heard “chipping” from the south end of Old Lime Road, San Juan. Reviewers mentioned that the observer did not have a binocular at the time of the sighting and did not provide details of how its congener, Pacific Wren (T. pacificus) was ruled out (2013-150; 3-4). A stub-tailed wren was seen, but not heard, on 15 November 2002 in Hotchkiss, Delta. This sighting occurred before the split of Winter Wren into three spe-cies (Chesser et al. 2010) and few were aware of the differences between the two ABA-area taxa in call notes, dorsal spotting, and coloration when the report was submitted. Much new information has been presented since 2002 on the topic of differentiating Pacific and Winter Wrens, so it is not surprising that the Committee did not accept this report (2013-246; 1-6).

Gray-cheeked Thrush – Catha-rus minimus. The report of a Catharus thrush at Crow Valley Campground, Weld, on 24 May 2012 fell one vote short of being accepted (2012-75; 5-2; 5-2; 5-2). After each of the three rounds of voting, the two “no” votes mentioned the thrush’s cheek color had not been described as cold gray a key field mark of C. minimus. Un-like in the East, the primary confu-sion species for Gray-cheeked Thrush in Colorado is Hermit Thrush rather

than Swainson’s Thrush (Leukering 2007, 2015b).

Swainson’s (Russet-backed group) Thrush – Catharus usutulatus. Swain-son’s Thrush subspecies breeding on the Pacific slope, known as Russet-backed Thrush, have been recorded as spring migrants in Colorado (Mlodi-now et al. 2013 and references there-in). They differ from the form that breeds in Colorado (C. u. swainsoni) Olive-backed Thrush, by their rus-set back coloration and dark flanks (among other features) often looking similar to Veery (C. fuscescens). Some Committee members thought that the photograph of a thrush from Chico Ba-sin Ranch, El Paso, on 15 September 2013 (2013-226; 3-4) did not show enough russet tones on its back to be properly considered referable to the Russet-backed Thrush group.

Bendire’s Thrasher – Toxostoma bendirei. The difficulty of differentiat-ing the very-rare-in-Colorado Ben-dire’s Thrasher from juvenile Curve-billed Thrasher (T. curvirostre) and worn adult Sage Thrasher (Oreoscop-tes montanus) remains a stumbling block for the Committee. This report was of a single Bendire’s from north of Del Norte, Saguache, on 20 June 2000 (2012-212; 1-6). Although Curve-billed Thrasher is very rare, at best, in the San Luis Valley, Sage Thrasher is a common local breeder.

Smith’s Longspur – Calcarius pictus. One was reported from Cherry Creek State Park, Arapahoe, on 30 April 2013 (2013-133; 1-6). Reviewers’ comments indicate that this report was not ac-cepted mostly for a lack of photograph-ic evidence and the scanty description.


Louisiana Waterthrush – Parkesia motacilla. A 7 September 2011 water-thrush was described from below the dam at Two Buttes Reservoir SWA, Baca (2013-3; 2-5). Reviewers com-mented on the late date for this spe-cies and that the throat streaking was not described, which would help dif-ferentiate it from the more common congener, Northern Waterthrush (P. noveboracensis).

Bay-breasted Warbler – Setophaga castanea. A report came from 22 Sep-tember 1992 of a Bay-breasted War-bler at what was then, and still is, a migrant trap, Last Chance, Washing-ton, (2013-275; 5-2; 4-3). Reviewers commented on the elapsed time (23 years) between the sighting and the report submission and that the expe-rienced observer did not separate this species from two look-alike species, Pine Warbler (S. pinus) and Blackpoll Warbler (S. striata).

Eastern Towhee – Pipilo erythroph-thalmus. One was reported from Cot-tonwood Canyon, Baca, on 12 May 2012 (2012-60; 5-2; 3-4). This audio-only report was felt by the Commit-tee to require plumage details, as the species, like most passerines, learns its song, so the bird may have been a hy-brid (which are depressingly regular in Colorado) or a confused Spotted To-whee. The well-known migrant trap,

Lamar Community College Woods, Prowers, was the location described as harboring a wintering towhee, 7 Janu-ary 2013 (2013-36; 4-3; 2-5). As more photographic documentation was submitted before the second round of voting, some reviewers commented on visible white spotting on the tertials and on wing coverts suggesting a hy-brid Eastern x Spotted Towhee.

LeConte’s Sparrow – Ammodramus leconteii. Four Committee members thought the description of this sparrow from below the John Martin Reser-voir bunkhouse, Bent, on 4 April 2013 (2013-97; 3-4) did not rule out the oth-er similar Ammodramus sparrows, espe-cially Nelson’s Sparrow (A. nelsoni).

Common Redpoll – Acanthis flam-mea. Now that Hoary Redpoll (Acan-this hornemanni) has been documented as occurring in Colorado, Commit-tee members voiced concern about Hoary Redpoll not being eliminated in the report, especially evident after the second round of voting (2013-42; 5-2; 2-5). The bird was described from South Fork, Rio Grande, on 2 January 2013. Another, reported on 2 April 2013 from near Clark, Routt (2013-94; 1-6) was believed by the Committee to be a redpoll, but their concern was with the scanty and vague details in the description not eliminating other look-alike species.

rePOrTers ANd CiTed OBserVersThe CBRC thanks the following individuals for submitting records of or discovering and reporting the rare species in Colorado discussed in this report: Dale Adams, Chuck Aid, Susan Allerton, Larry Arnold, Ben Bailey, Jason Beason, James Beatty, Robert Beau-champ, Dan Belter, Brad Biggerstaff, JD Birchmeier, Maggie Boswell, Robert Bradley, John Breitsch, Peter Burke, Frank Cada, Mark Chavez, Eric DeFonso, Peter Derven, Coen Dexter, Scott Dieni, Craig Dodson, Edward Donnan, David Dowell, John Drum-mond, Kathy Mihm Dunning, David Ely, Lee Farrell, Doug Faulkner, Peter Gent, Brian


Gibbons, Nancy Gobris, Doug Gould, Laurens Halsey, Judith Henderson, Mike Henwood, Robb Hinds, Rachel Hopper, Charles Hundertmark, Bev-erly Jensen, David Johnson, Bonnie Kaake, Bill Kaempfer, Kevin Keirn, Joey Kellner, Amy Kenyon, Loch Kilpatrick, Michael King, Hugh Kingery, Gary Koehn, Nicholas Komar, Kaye Lafreniere, David Laliberte, David Leather-man, Tony Leukering, Norm Lewis, Thomas Litteral, Carl Lundblad, Eric Lutomski, Cynthia Madsen, Luis Matheus, Bill Maynard, Tom McConnell, Rich Miller, Mark Minner-Lee, Steven G Mlodinow, Larry Modesitt, Nick Moore, Andrew Morris, Riley Morris, SeEtta Moss, Polly Wren Neldner, Duane Nelson, James Nelson, Andrea Niess, Charlie Nims, Michael Obrien, Ric Olson, Steve Olson, Ken Pals, Scott Pendleton, Brandon K. Percival, Guillaume Peron, Kris Petersen, Mark Peterson, Laurence Pitcher, Greg Prelich, Rob Raker, Andrea Robinsong, Dorothy Russell, Tim Ryan, Bill Schmoker, Cathy Sheeter, John Shenot, Aaron Shipe, Randy Siebert, David Silverman, Steve Stachowiak, Jane Stulp, Richard Taylor, Cheryl Teuton, Jim Thompson, Jackson Trappett, Van Truan, Brian Underwood, John Van-derpoel, Glenn Walbek, Sean Walters, Christopher Warneke, Marty Wolf, Jimmy Woodard, Randi Young.

liTerATure CiTedAmerican Ornithologists’ Union. 1998. Checklist of North American Birds.

Lawrence, KS: Allen Press.American Ornithologists’ Union (AOU). 1998. Check-list of North Ameri-

can Birds. Lawrence, KS: Allen Press.Howell, N.G., and J. Dunn. 2007. A Reference Guide to Gulls of the Ameri-

cas. Houghton Mifflin Company. Boston New York. pp. 482-483.Bull, E. L. and C. T. Collins. 2007. Vaux’s Swift (Chaetura vauxi) The Birds of

North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithol-ogy; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/077.

Chesser, T. R., Banks, R. C., Barker, F. K., Cicero, C., Dunn, J. L., Kratter, A. W., Lovette, I. J., Rasmussen, P. C., Remsen, Jr., J. V., Rising, J. D., Stotz, D. F., and K. Winker. 2010. Fifty-first Supplement to the American Ornithologists’ Union check-list of North American Birds. Auk 127 (3): 726-744.

Chesser, T. R., Banks, R. C., Burns, K. J., Cicero, C., Dunn, J. L., Kratter, A. W., Lovette, I. J., Navarro-Siguenza, A. G., Rasmussen, P. C., Rem-sen, Jr., J. V., Rising, J. D., Stotz, D. F., and K. Winker. 2015. Fifty-sixth Supplement to the American Ornithologists’ Union Check-list of North American Birds. Auk 132(3): CSi-CSxvi.

Maynard, B. 2014. A Costa’s Hummingbird (Calypte costae) in Colorado Springs. Colorado Birds 48:199-203.

Cardiff, Steven W. and Donna L. Dittmann. 2000. Brown-crested Fly-catcher (Myiarchus tyrannulus) The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/496doi:10.2173/bna.496.


eBird. 2012. eBird: An online database of bird distribution and abundance. eBird, Ithaca, New York. Available: http://www.ebird.org. [Accessed: Au-gust 10, 2015.]

Howell, S. N. G., and J. Dunn. 2007. Gulls of the Americas. Houghton Mif-flin, Boston.

Johnson, T. 2013. Answers to July Photo Quiz. Birding 45(5):48-52. Faulkner, D. 2012. The 63rd Report of the Colorado Bird Records Commit-

tee. Colorado Birds 46:188-197.Lee, C-T., Birch, A., and T.E. Eubanks. 2008. Field identification of Western

and Eastern Wood-Pewees. Birding 40(5):34-40. www.aba.org/birding/v40n5p34.pdf

Leukering, T. 2007. Gray-cheeked Thrush. Colorado Birds 41:59-62.Leukering, T. 2008. Glossy Ibis and the identification challenges of hybrid

Plegadis in Colorado. Colorado Birds 42:147-149.Leukering, T., and N. Pieplow. 2010. Pacific and Winter Wrens. Colorado

Birds 44:281-286.Leukering, T. 2015a. Ravens in Colorado: An impossible field identification?

Colorado Birds 49:255-262.Leukering, T. 2015b. The unfamiliar familiar Hermit Thrush. Birding

47(4):54-56.McNair, D. B. and T. E. Lewis. Vaux’s Swifts overwinter at a roost in Apala-

chicola, Florida. 1997. Fla. Field Nat. 25(2):54-57.Mlodinow, S. G., T. Leukering, and N. Pieplow. 2013. “Russet-backed”

Swainson’s Thrush. Colorado Birds 47:135-142.Pieplow, N. 2014. Common vs. Chihuahuan Ravens. Earbirding.com (http://

earbirding.com/blog/archives/4736). [Accessed 4 August 2015]Sibley, D. A. The Sibley Guide to Birds, Second Edition. 2014 Alfred A.

Knopf, New York.

Mark Peterson, [email protected] Maynard, [email protected]


Computer Modeling to Improve Flock-sizeEstimatesAlyssa H. RawinskiMonte Vista Middle School Science Fair Project 2015

AbstractThe National Audubon Society predicts 314 species of birds

are inching closer to extinction because of climate change. It will be very important for biologists and bird watchers to estimate bird numbers accurately as bird populations are monitored. I chose to test traits, skills and characteristics that may affect bird count-ing accuracy. I used the Jack Hodges computer model/simulation Wildlife Counts to determine whether training improved esti-mating accuracy. I randomly selected biologists and bird watch-ers from a local list. Each participant was shown screens with an unknown number of birds, and was asked to estimate the flock size. In general participants made significant improvements after being trained using Wildlife Counts. Comparisons of groups (i.e. biologist vs. bird watcher, male vs. female, caffeine vs. no caffeine, artist vs. scientist) yielded no significant differences. Within each group, all members demonstrated a significant improvement in estimating flock size after training. I also used real bird photos and found there were significant differences between simulation and real bird photo estimates. This seems to indicate that there are other factors that may affect counting accuracy. One report said people tend to underestimate numbers in large flocks. My find-ings agree with that statement, even after training. In conclusion, there were no specific characteristics that affected the accuracy of flock size estimates, meaning that all individuals, regardless of background and traits, can count birds and improve through prac-tice with the simulation. Training study participants using the Wildlife Counts program significantly improved their estimates of flock size. Similar training for anyone who monitors bird popula-tions is recommended.

IntroductionAccording to the National Audubon Society (NAS), bird pop-

ulations may be facing serious threats and declines due to global warming and climate change (Nijhuis, 2014). It will become very important for biologists and bird watchers to estimate bird numbers accurately.


Fig. 1. Example of Simulation Screen. Guess how many birds are there!

When I read the NAS article, I realized how important it is to estimate bird numbers accurately and keep track of bird populations. I thought it would be a good idea to test traits, skills and characteris-tics in people that might affect bird counting accuracy. Some of those traits, skills and characteristics that I chose to test included biologist/bird watcher, male/female, use of caffeine within five hours/no caf-feine within five hours and artist/scientist. I wanted to know if there were any differences between these groups.

I reviewed the proceedings of an International Symposium held in Asilomar, California called Estimating Numbers of Terrestrial Birds (Ralph, J.C. and M.J. Scott, 1980). I checked to see if any of the papers had used computer simulations to improve estimating accu-racy and found that none did. This is probably because the paper is dated 1980 and computers were just starting to be used at that time. I did not find any other literature that referenced use of computer simulations to improve bird counting accuracy (other than the Jack Hodges, Wildlife Counts computer simulation, which I used in my ex-periment).

Within these same proceedings, Kepler and Scott (1980) de-scribed that variability can be reduced by training observers. I wanted to see if Wildlife Counts could improve estimation accuracy. A presen-tation by Harrington in 1999 stated that people counting birds tend to underestimate when large numbers of birds are viewed. I wanted to use my data to see if that principle held true.


Methods and MaterialsFor this experiment, I designed four different tests using the Jack

Hodges computer model/simulation Wildlife Counts. The model shows simulated images of birds while it knew the exact number of birds on the screen. For all tests the participants were told that the range of birds was 50-600. For my experiment, I used the “Swans on a Lake” simulation (Fig. 1). I was able to obtain 32 participants for this project, and their results were kept confidential.

For Test 1, the participants were asked to look at five screens, all with different numbers of birds in them, for a certain amount of time, and then write down their estimate after each screen was shown. This was considered the “pre-training” test, and was used to show how well the participants did without any training.

Test 2 was used as the training session. The participants were shown screens with 20, 50, 100, 300, and 500 birds in them, and were told the actual number. This helped the participants cali-brate their eyes. Then, participants were shown five more screens of birds. They wrote down their estimates and then were shown the actual number of birds in the image immediately. This was used to let the participants know how well they were doing and what kind of changes they needed to make to increase their esti-mating accuracy.

Test 3 was the “after-training” test. The participants were again shown five computer screens, after which they would write down their estimate. We did not tell the participants that the numbers of birds were exactly the same in Test 1 and Test 3. This allowed me to see if there was improved accuracy after training because the actual numbers were held constant. Test 3 was used to determine if the par-ticipants’ accuracy improved after training.

Test 4 was a series of three actual bird photographs. I used Corel Photo Paint Software to pre-count and modify bird numbers in the photos so that each photo matched the number of birds in one of the screens in Test 1 and Test 3. The participants would be shown the three photos, and then write down their guess. This test was used to show how accurately the participants could estimate real birds, after all the simulations. This allowed me to compare the photo bird num-ber to a corresponding simulation number since they had the same number of birds.

ResultsThere are two primary statistics used throughout this experiment.

One is the average estimate for a group. For example, if 10 biologists write down their estimates, an average can be produced. If 10 bird-


Table 1: Summary of Group Analysis.

Summary of Group Analysis For Test 1 and Test 3

Group/Comparison*Average Absolute

Error for First Group Listed

Average Absolute Error for Second Group Listed Significance**

All T1 vs. All T3 567 314 Extremely

Bio T1 vs. BW T1 510 606 Not

Bio T3 vs. BW T3 285 334 Not

Bio T1 vs Bio T3 510 285 Very

BW T1 vs. BW T3 606 334 Extremely

Male T1 vs. Female T1 529 597 Not

Male T3 vs. Female T3 269 350 Not

Male T1 vs. Male T3 529 269 Extremely

Female T1 vs. Female T3 597 350 Very

Caf T1 vs. Ncaf T1 507 621 Not

Caf T3 vs. Ncaf T3 318 311 Not

Caf T1 vs. Caf T3 507 318 Significant

Ncaf T1 vs. Ncaf T3 621 311 Extremely

Art T1 vs. Sci T1 659 526 Not

Art T3 vs. Sci T3 338 305 Not

Art T1 vs. Art T3 659 338 Very

Sci T1 vs. Sci T3 526 305 Extremely

*Abbreviations Include: Bio=Biologist; BW=Bird Watcher; Art=Artist; Sci=Scientist; Male=Male; Female=Female;T1=Test 1; Caf=People who had caffeine; Ncaf=had no caffeine; T3=Test 3

** Categories include: not significant=<90% confidence; significant=90-98% confidence; very significant=98-99% confidence; extremely significant=>99% confidence

watchers provide estimates for that same screen, another average can be produced. This is comparing actual bird estimates that participants made, and is usually done within a single screen of a known number of birds. Averages therefore can be compared among groups or to ac-tual numbers.

Another statistic I call the “absolute error” of an estimate. The plain and simple way to define absolute error is the number of birds, either above or below, that the participant guessed compared with the actual number of birds. Absolute error is used to determine the error for a participant across the five screens. For example, if a participant


The author presenting her poster, “Do Certain Traits, Skills, or Characteristics Affect Bird Estimating Accuracy, and Can a Computer Model Improve Estimating Accu-racy? You Can Count on it!”

estimates that there are 250 birds on the screen when there are ac-tually 412 birds, the absolute error (expressed as a positive number) would be the difference, in this case 162. Adding the absolute error for each of the five screens, you get the total absolute error for that person, which might be 470. If another person’s total absolute error was 325, then that person’s total error was lower. The total absolute error could be added together and averaged for each group. It should be noted that the Hodges simulation allows for the cancellation of er-rors. I chose not to allow cancellation of errors because it is like shoot-ing two arrows at a bull’s eye, hitting 10 inches high, and then 10 inches low. The two hits, high and low, should not make a bull’s eye.

I used GraphPad, QuickCalcs 2014 to run my t-tests to compare means and determine significance. The analysis used both paired and unpaired samples.

Table 1 lists the summary of group analysis. It shows one group compared to another (example: male vs. female), and also one group compared to the same group (example: male Test 1 vs. male Test 3). It also shows the significance of the averages for each group.

Fig. 2 shows how each group improved after training, and the re-duction in their errors.


Compare Simulated Screens to Real Bird Images: Average Estimates for All Participants Test 3 vs. Test 4

Test 3 (76 birds)Average Estimate

Test 4 (76 birds)Average Estimate Significance

78 76 Not significant


Test 4 (536 birds) Average Estimate Significance

451 315 Extremely significant


Test 4 (132 birds) Average Estimate Significance

118 143 Significant

Table 2 shows the Test 3 vs. Test 4 results for each screen. Test 3 used simulated bird screens compared with Test 4, which used real bird photographs of the same number of birds.

Discussion and ConclusionsDid Traits, Skills or Other Characteristics Have an Effect on Bird

Table 2: Test 3 vs. Test 4 Results.

Fig. 2: How each group improved after training, and the reduction in their errors.


Estimating Accuracy? Table 1 shows the differences in one group vs. another. For example, were males more accurate than females? In all cases (biologist vs. bird watcher, male vs. female, caffeine vs. no caffeine, artist vs. scientist) there were no significant differences be-tween any of the groups. This means that traits, skills and charac-teristics don’t significantly affect counting accuracy. It also means that any person, regardless of characteristics, can potentially improve bird-counting accuracy through training.

How Did Accuracy Change From Simulation Screens to Real Life Bird Photographs? By testing the participants using real bird photographs compared to the simulation screens, I found out that when numbers are low, people are more accurate with estimating, as shown in Table 2. As numbers of birds in the photographs increased, there were sig-nificant differences between simulation screen estimates and real bird photo estimates. This may be due to the fact that there are more challenges when estimating real bird numbers. Difficulties such as background, types of birds, overlapping birds, and density may all af-fect bird estimating accuracy.

Over and Underestimation. Harrington (1999) said that people tend to underestimate numbers of birds in large flocks, and my find-ings are consistent with that statement. In Test 1, 85 percent of the estimates were lower than the actual number and in Test 3, 72 per-cent of the estimates were lower. I believe that the training had to do with the change in percentages.

Did the Jack Hodges Computer Simulation Wildlife Counts Improve Bird Counting Accuracy? Table 1, line one, shows the absolute errors for all of the participants in Test 1 and Test 3. As you can see the participants made extremely significant improvements after training (error was reduced). This data agrees with Kepler, et al. (1980) in that training reduced bird counting variability. Bird counters around the world should consider using the online or purchased editions of Wildlife Counts computer simulation model to improve their bird counting accuracy. The model is available at wildlifecounts.com.

Why Accurate Bird Estimating is Important. In the coming years, bird populations are expected to decline because of climate change. With all of these potential changes in bird populations, accurate bird estimates and population data will be very important to the future of these species. Using the Jack Hodges Wildlife Counts computer simulation, most participants’ estimates improved. Although there were no specific characteristics that effected bird estimating accu-racy, training participants with a computer model did improve ac-curacy, and that may be the future for keeping precious bird species accounted for and protected!


So how many birds did you guess were in Fig. 1? There were actually 360 birds!

ACkNOwledgemeNTsFirst of all, I would like to thank all of the participants who contributed to my experi-ment. Thank you as well to Mr. Jack Hodges for providing the simulation software. I would also like to thank my teachers, Mrs. Gina Randolph and Ms. Loree Harvey, for being so helpful. And last but not least, I would like to thank my family, especially my dad, for helping me whenever I needed it. So thank you all, I couldn’t have done it without you!

liTerATure CiTed“Bird Counting 101.” eBird. Audubon and Cornell Lab of Ornithology, 23 Feb. 2012.

Web. 29 Sept. 2014. <http://ebird.org/content/ebird/news/counting-101/>.Harrington, B. (1999, July 21). Estimating Numbers of Birds in Flocks. Retrieved 2015,

from www.audubon.org/sites/.../estimating_flocks.p.. A power-point presentation.Hodges, J., 2013, Wildlife Counts. A training tool for wildlife population estimation. A

computer simulation computer simulation. Wildlifecounts.comKepler, C., & Scott, M. (1980). Reducing Bird Count Variability by Training Observers.

In: Estimating Numbers of Terrestrial Birds, C. John Ralph and J Michael Scott, Editors, Proceedings of an International Symposium held at Asilomar, California, 1980, 366-371. Retrieved February 2, 2015, from https://sora.unm.edu/sites/default/files/journals/sab/sab_006.pdf

Nijhuis, M. (2014, September 1). A Gathering Storm for North American Birds. Audu-bon, 25-32. Volume 116

QuickCalcs , T-Test Calculator. (2014). Retrieved December 1, 2014, from http://www.graphpad.com/quickcalcs/ttest1.cfm

Ralph, J.C. ad J.M. Scott, 1980. Estimating Numbers of Terrestrial Birds. Proceedings of an International Symposium, Asilomar, California. Cooper Ornithology Society, Studies in Avian Biology No.6. 641 p.

Alyssa H. Rawinski, [email protected]


A Loggerhead LarderDave Leatherman

The job opening is that of biological technician for a natural re-source agency with land management responsibilities on the north-eastern plains of Colorado. It’s the kind of job I would have jumped at back in the 1970s with a formal description that might read some-thing like this: “Inventory, collect and curate fauna from within an assigned area of native grassland. Applicants must be familiar with the life histories and diurnal habits of the insects, small mammals, passerine birds, reptiles and amphibians of Weld and surrounding counties. Work conditions include variable and potentially harsh weather, venomous snakes, barbed wire, cattle (including bulls), truck traffic and plants with thorns. Must be willing to have work habits and performance evaluated by at least one other technician on a regular basis. Pay commensurate with education and experience.”

In the text and photographs that follow, I intend to make a case for the United States Forest Service or Colorado Department of Parks and Wildlife hiring a certain male Loggerhead Shrike (Lanius ludovicianus) to fill the job opening described above. This one bird, operating on Weld County Road 37 between Roads 114 and 122 dur-ing the summer of 2015, would not only warrant hiring, but a promo-tion, a letter of commendation and a 2016 rehire. In fact it did such a good job of collecting and displaying biota that I was in awe of its appreciation for diversity and was taken aback on more than one oc-casion by its lethal efficiency. He was an exhibitionist in every sense of the word.

No doubt, as soon as humans began noticing shrikes in the natural world around them, their habit of sticking objects on sharp things became a source of curiosity. Our grandparents called them “butcher birds” and probably never used benign descriptors in their company. From our perspective, impaling creatures on sharp objects, especially when often the stickees are alive at the time of the act, and not eaten right away, or at all, can easily be interpreted as “mean” or “macabre.” So why do they do it? These unique raptorial songbirds have sharp, falcon-like beaks equipped with a pair of tomial teeth on the maxilla for severing the spinal columns of their prey (Craig 1978). And like hawks they have the skills to discover and catch things. But why stick them? The answer seems partly attributable to their relatively weak feet that lack talons (Yosef 1996). In essence, the act of prey consumption is made easier by use of sharp objects, both natural and unnatural, that function as “forks.”

THE HUNGRY BIRD


Fig. 2. Redshank grass-hopper. Legs removed by shrike to make the handling and impaling easier.

Fig. 1. Redshank grasshopper impaled intact by Loggerhead Shrike as found 18 June 2015 on Weld CR37 0.9 miles north of CR114. This particular species is per-haps the most commonly utilized insect by shrikes on the eastern plains of CO.

Fig. 3. Robust camel cricket, second most commonly impaled insect in many parts of eastern Colorado.

Fig. 4. A second species of robust camel cricket.

Fig. 5. Field cricket.Fig. 6. Ground beetle head and thorax. Fig. 7. Darkling beetle.


But there’s more to impaling potential food items than that. A common theme throughout the Animal Kingdom is males showing off in various ways to females as a prelude to reproduction. The Log-gerhead Shrike, the only one out of 30 true shrike species in the world that occurs wholly within North America, is mostly migratory throughout the northern part of its range, including Weld County, CO (Kingery 1998, Craig 2014, Yosef 1996). In spring males arrive on breeding grounds before females. Usually for a period of weeks af-ter the males arrive, an increasing frenzy of “bulletin board” activity occurs, with these hormone-driven individuals impaling things all over territories they think would be productive places to raise families. Colorado Breeding Bird Atlas I fieldworkers documented shrike courtship as basically a May activity (30 April to 6 June) (Kingery 1998). During this timeframe, males show off their skills at providing food for prospective mates and their resultant broods. During the two mid-June visits in this episode, I believe the nest was occupied and that the adults were in the process of whittling away at the male’s stash of food.

I have long been enamored of shrikes and their penchant for im-paling prey. Odd objects on barbed wire fences catch my eye. See-ing an impaled grasshopper here, a cricket there is not uncommon anywhere in Colorado where shrikes breed, and particularly not at a known stronghold like the Pawnee Grasslands. But I wasn’t prepared for what I saw on 18 June 2015 along CR37 north of CR114 between the Owl Creek Bridge and the Central Plains Experimental Range Headquarters complex to the north. There on metal fence barbs on both sides of the road within about 100 meters both north and south of a lone Siberian elm (1.1 miles north of CR114), was an excep-tional assortment of shrike-impaled biota. I did not do an exact count but would estimate at least 75 objects.

Insects were by far the most common animal group impaled. Most were what I have learned to be the “favorite” of shrikes on the eastern plains of Colorado, the redshank grasshopper (Xanthippus corallipes) (Figs. 1 & 2). These large, band-winged hoppers (family Acrididae, subfamily Oedipodinae) are widely distributed in the West and usu-ally abundant on the arid plains. Their bright red inner “thighs” on the hind jumping legs are distinctive, although my friend Tim Mc-Nary, an orthopteran expert extraordinaire, reminds me that there are a few other lookalike species in this genus.

Next in abundance among the six-legged larder were large crickets

All photos taken on either 18 June or 22 June (except for the one showing a pellet) by Dave Leatherman within 0.9 and 1.1 miles north of Weld CR114 along CR 37.


in the family Gryllacrididae, mostly reddish-brown but some creamy-tan. These so-called robust camel crickets (Udeopsylla robusta) (Fig. 3) and perhaps another species (Daihinia brevipes?) (Fig. 4) live in burrows in the soil or hide under objects like dry cow pies and are most active at night (Cranshaw 1995). Because male crickets are more apt to forage away from burrows (for other insects and a lim-ited amount of plant material), it is likely more males are caught and impaled by shrikes than females, however, this needs to be verified.

Several black field crickets of both genders (Gryllus sp.) decorated the fences (Fig. 5).

There was one large predaceous ground beetle head (family Ca-rabidae, genus Pasimachus) (Fig. 6) and one medium-sized darkling beetle (family Tenebrionidae, probably Eleodes sp.) (Fig. 7).

As for reptiles, on 18 June the only representative taxon were four, small (about half-grown), intact, Short-horned Lizards (Phrysonoma hernandesi) (Fig. 8). On 22 June the number of “horny toads” was the same but it was obvious something, presumably a shrike, had eaten part of the upper torso of one, accessed from the underside (Fig. 9). Added to the reptilian ranks of the run-through were a Lesser Earless Lizard (Holbrookia maculata) (Fig. 11) and a small Western Hognose Snake (Heterodon nasicus) (Fig. 12). This lizard, multiple individu-als of which I have seen impaled in other eastern CO locations, was partially shriveled, but its inner organs appeared to have been at least partly removed. The head end of the snake was missing.

Loggerhead Shrikes are known to impale small mammals, at times in good numbers, but never as commonly as their relative, the North-ern Shrike (Lanius excubitor) (Yosef 1996). The remains of only one mammal hung from a barb in this situation, what I think was a young Thirteen-lined Ground-Squirrel (Ictidomys tridecemlineatus) based on the shape of the skull and the color of hairs still attached to the car-cass (Fig. 13).

What seemed exceptional to me about this situation, in addition to the sheer number of objects, was what this shrike imposed on other birds. In addition to finding adults, it also found new nestlings, some that were essentially featherless (Figs. 15 & 16). Not only did it find birds smaller than itself, it apparently killed one bigger than itself, a juvenile Western Meadowlark (Sturnella neglecta) (Fig. 14). Some of its bird victims were affixed to a wire whole, others were beheaded. I must admit that on 18 June, even as a lifelong biologist, coming across the beautiful, unbloodied head of a Brewer’s Sparrow (Spizella breweri) with its lifeless, hollow stare, stopped me in my tracks (Fig. 17). I later found a headless Brewer’s Sparrow body over a hundred meters away that may have been its match. This shrike was not mess-


Fig. 8. Young short-horned lizard intact on 18 June 2015.

Fig. 9. Same individual short-horned lizad as shown in Fig. 8 as discovered on 22 June 2015 show-ing partial consumption after being impaled.

Fig. 10. Short-horned lizard head as discov-ered on 7 August 2015.

Fig. 11. Lesser earless lizard. Fig. 12. Western hognose snake.


Fig. 13. Unknown mammal (probably young 13-lined ground-squirrel). Skull showing black mouth cavity at lower left part of carcass. Fig. 14. Young Western Meadowlark,

presumably impaled by shrike.

Fig. 15. Nestling bird (species unknown). Fig. 16. Nestling bird (species unknown).

Fig. 18. Pellet, presumably of shrike, impaled by shrike.Fig. 17. Brewer’s Sparrow head.


ing around. Altogether I would estimate I saw a total of 10 impaled birds, most quite young, that had to have been taken from nests.

So a total of about 75 objects: 6 reptiles, about 10 birds, one mam-mal and roughly 58 insects, most of the latter group being rather large grasshoppers and crickets. The major differences in the larder be-tween 18 and 22 June were that many of the objects that were whole on the first visit were partially or mostly consumed on the second visit. Plus there was the addition of two reptile species. The male shrike doing the impaling seemed to accomplish what were likely his two primary objectives: storing food for later consumption and attracting a mate.

As a follow up, I revisited the site on 7 August 2015. Mostly I drove the stretch of road on either side of the nest tree, but also walked some of it. The only identifiable object I found from the June larder was the head of one Short-horned Lizard (see Fig. 10). A re-gurgitated bird pellet, which appeared to be the right size for a shrike, was also new on the fence very near the shrikes’ nest elm (Fig. 18). And yes, I saw at least three fledged shrikes. Asking them the ques-tion, “who’s your daddy?” seemed unnecessary. They were hunting on their own, usually by flying down to the ground from the top strand of the fence. Twice I observed them returning to the fence with small insects, probably grasshopper nymphs, which they held against the wire with a toe, and consumed on the spot.

In closing, my curiosity keeps returning to that impaled Brewer’s Sparrow head and those nestling birds. These objects perhaps fit within the standard reasons for impaling by shrikes cited in the lit-erature, but struck me as possibly serving a third purpose–that of in-timidation. It reminded me of something I saw once as a kid in a Na-tional Geographic Magazine involving cannibals in Borneo who, as a warning to would-be intruders, displayed heads on sticks. If whole birds are usually impaled (as was the meadowlark and most of the nestling birds), why did this male shrike go to the trouble of carefully beheading a sparrow and then, apparently, place the resultant two body parts at opposite ends of his territory? Did this, along with the impaling of nestlings, convey to other species nesting, or even con-sidering nesting within this shrike’s territory, that competing with him for food resources might be a bad idea? No way to prove any of this, but one has to wonder.

Regardless of answers to these last conjectures, if I was an HR per-son looking to fill a biodiversity surveyor position, and a male shrike was sitting across the desk, I’d ignore the bad recommendation in the application folder from somebody’s grandmother. Hire him!


ACkNOwledgmeNTsI thank Tim McNary and Dr. Boris Kondratieff, both affiliated with the C.P. Gillette Museum of Arthropod Diversity at Colorado State University, for assisting with identifications of impaled insects.

liTerATure CiTedCraig, R. B. 1978. An analysis of the predatory behavior of the Loggerhead

Shrike. Auk 95:221-234.Craig, Susan. 2014. Movements, migration and breeding by Loggerhead

Shrikes (Lanius ludovicianus) in eastern El Paso County, Colorado. CO Birds 48(2):266-271.

Cranshaw, Whitney and Boris Kondratieff. 1995. Bagging big bugs. Fulcrum Publishing, Golden, CO.

Kingery, Hugh E. (ed.). 1998. Colorado breeding bird atlas (I). Co-published by Colorado Bird Atlas Partnership and Colorado Division of Wildlife, Denver.

Yosef, Reuven. 1996. Loggerhead Shrike (Lanius ludovicianus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithol-ogy; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/231

Dave Leatherman, [email protected]


Ravens in Colorado: An Impossible Field Identification?Tony Leukering

Colorado hosts two species of ravens, the holarctic Common Raven (Corvus corax), grist for many an authorial mill (includ-ing that of Poe), and the limited-range Chihuahuan Raven (Cor-vus cryptoleucus), which has probably seen little, if any, poetry or prose written about it. Common Raven is represented in Colorado by the subspecies sinuatus. Its range is largely restricted to West Slope and montane habitats in Colorado, including on the Mesa de Maya, which extends from Las Animas County into Baca, Bent and Otero counties. Common Ravens are also regularly seen on the northwest plains adjacent to the foothills, typically west of I-25 though with some exceptions [especially westernmost Arapahoe County and the vicinity of Rocky Mountain Arsenal N. W. R. in Adams County (eBird 2015)] and on the plains in the Arkansas River drainage. The Chihuahuan Raven’s range is something of an enigma. Henshaw (1875) reported the species as widespread on the Colorado plains during the period of American Bison slaugh-ter (mid- to late 1800s), but its range contracted greatly following the near extinction of wild bison in the United States, possibly returning to pre-slaughter range (Aiken and Warren 1914). The first Colorado Breeding Bird Atlas presented the breeding range of Chihuahuan Raven as restricted to 11 southeastern counties: south from southern Pueblo County east to southern Prowers County, with scattered records north through Crowley and Kiowa counties and single records from the southern borders of El Paso and Chey-enne counties (Nelson 1998).

With the great increase and intensity of birding efforts in the state that began in the early 1990s (pers. obs.), sightings of Chihua-huan Ravens outside of the range mapped by Andrews and Righter (1992) and Nelson (1998) began to accumulate and seems to be accelerating (pers. obs.). There are eBird (eBird 2015) reports from 38 of the state’s 64 counties, including those as far north as Routt, Larimer and Weld and as far west as Mesa and Montezuma. The vast majority of these far-flung reports is supported by little or no defini-tive details, and therefore is not included in the public eBird data. But, what constitutes definitive details for two species so similar, that are entirely black in both plumage and soft-parts coloration? Aye, there’s the rub.

IN THE SCOPE


Back-cover Photo, Part IThe photograph on the back cover of this issue was taken in July

2015 and serves as an excellent illustrative piece for this essay. Clear-ly it’s a raven, but which species? Perhaps the following will assist in the bird’s identification.

Raven Identification“Distinguishing Chihuahuan Raven from small Common indi-

viduals can be extremely difficult.” (Sibley 2000)As indicated above, raven identification is at times, “extremely

difficult.” In fact, some birders (including yours truly) consider this the single most-difficult identification quandary in the ABA area. Yes, there are other very difficult groups, but how many are of such large birds that are often seen so well? My personal experience with raven identification in southeastern Colorado followed an interest-ing course. I first considered them quite difficult, then fairly straight-forward as I got more experience with them. However, as additional experience piled up, I’ve forced myself to keep an open mind and have now reverted, considering them to be at the very least quite dif-ficult to separate, if they’re definitively and reliably separable at all.

Due to the near-complete lack of plumage characters permitting sepa-ration (both are all black), birders in the New World area of sympatry or nearby have had to resort to shape and vocal clues to attempt raven iden-tification, with the various individual characters discussed below. Pieplow (2014) discussed the vocal aspects of raven identification, and given the difficulty of discussing vocalizations in a print medium, I highly recom-mend reading (and listening to) that post, including the comments.

Before tackling the individual characters that are typically used to attempt raven identification, please note the following caveats with regard to size. While Common Raven averages considerably larger than Chihuahuan Raven, there is enough variation in overall size in both species as to make an in-the-field distinction between a large Chihuahuan Raven and a small Common Raven problematic. Ad-ditionally, some of that variation in size is due to sex, with males in both species being larger than females in nearly all characters. In the treatment of individual characters below, all statements are of rela-tive size. You may also refer to the data presented in Table 1. As we all know, correctly assessing size in the field without some comparison, direct or indirect, is fraught with uncertainty. A direct comparison of size with some other bird species may be useful, but only with a suit-able yardstick: An American Crow mobbing a raven would provide a useful comparison, but a much smaller bird, such as a Western King-bird, would not, due to the significant size disparity.


Bill ShapeCommon Raven bills are longer and, generally, deeper than are

those of Chihuahuan Raven. With the overlap in bill depth between the two species, but the absolute greater length of bill in Common Raven, Common Raven generally appears to have a longer bill rela-tive to depth than that of Chihuahuan [midpoints of extreme ratios are length being 2.55x greater than depth in Chihuahuan, 2.81x in Common (Ratio of C:D); Fig. 1]. However, without direct compari-son, this character is probably nearly useless in field situations.

Nasal-bristle LengthThe nasal bristles are the feathers that lie atop the basal part of

the bill in all members of the genus Corvus, and much is made of this character’s usefulness in raven identification by some birders. The ex-tent of the bristles on Chihuahuan is generally more (often distinctly more) than half the bill length, while that of Common is generally less than half the bill length. This would mean that individuals with nasal-bristle length of about half the bill length are not identifiable using just this character. Additionally, there has been suspicion raised

Fig. 2. Two each Chihuahuan (left) and Common (right) Ravens (specimens at Mu-seum of Vertebrate Zoology, CA). Photo by Peter Pyle


about the true usefulness of the character in Colorado (B. Maynard pers. comm., S. Mlodinow pers. comm.), as most ravens assumed to be Chihuahuans in Colorado seem to lack the excessive nasal bristles typical of the species in the core of its range (Fig. 1). Whether this is due to misidentification of ravens on our part, variability in this character on the part of Colorado Chihuahuan Ravens or, egad!, a result of hybridization of ravens in Colorado is not determinable at this time. Suffice it to say that this character may not be particularly useful in the field, at least not in Colorado.

Color of the Base of Neck and Breast FeathersChihuahuan Raven used to be known by the moniker White-

necked Raven due to the fact that the base of the neck and breast feathers is white versus the gray of the same feather bases in Common Raven. However, given that looks at these feather bases good enough to provide certainly of the color just about requires having the bird in question in the hand, that means that this character’s usefulness is akin to, but probably less useful than, that of the brown neck ring in male Ring-necked Ducks. At least with the duck, if you can see the bird well enough to note the brown neck ring, you certainly have a sufficient view to note all of the other much-more-obvious identifi-cation features! In order for the white feather bases to be seen, the feathers usually need to be ruffled by the wind. Pyle (1997) presents this caution: “Beware that the throat and breast plumage differences can be subtle, particularly without direct comparison.” And that in a publication aimed at bird banders with birds in the hand! Some observers report seeing single Common Ravens in very windy con-ditions exhibiting apparent white bases to these feathers in direct comparison with gray feather bases on other Common Ravens in the same flock (S. Mlodinow pers. comm.).

Throat ShagginessThis character is created by the long feathers of the throat, with

Chihuahuans having, generally, shorter such feathers than do Com-mons. However, given the overlap in the range of values in the two species, and the difficulty in correctly assessing the feature in the field [the non-overlapped part of the Common range is only 14 mm (0.55 in.)], this is probably another character with limited field use-fulness.

Wing Length and ShapeCommon Raven may have longer wings, relative to overall size,

than does Chihuahuan [at least Sibley (2000) seems to present the


Chihuahuan Raven Common Raven (sinuatus)

Character Female Male Female Male

Wing chord 321-361 (100) 332-380 (100) 390-425 (19) 412-440 (17)

Tail length 179-205 (20) 181-214 (20) 218-242 (19) 225-250 (17)

All All

Wing chord 321-380 (200) 390-440 (36)

Tail length (A) 179-214 (40) 218-250 (36)

r1-r62 (B) 25-45 34-633

Ratio of B:A4 0.14-0.21 0.16-0.25

Length of longest throat feathers

29-42 39-56

Bill length5 (C) 49.5-59 63-71 (14)

Bill depth6 (D) 20-22.5 21.7-26.1

Ratio of C:D4 2.48-2.62 2.72-2.901 All values from Pyle (1997) except those of Bill length of Common Raven are from Oberholser (1918)2 The differences in length between innermost (r1) and outermost (r6) rectrices, a measure of "wedged-ness"3 Pyle (1997) provides this measure for the species as a whole, not for sinuatus, which is a medium-sized subspecies.4 Range obtained by comparing minimum value of both variables and maximum value of both variables5 Exposed culmen measurement; that is from base of bill to tip6 Measured at nares

species that way], but if so, any difference is probably not reliably detectable in the field. Sibley (2000) also presents a different wing-tip shape in the two species, with Chihuahuan wings more square- or round-tipped versus more pointed Common Raven wings, but this difference is much less apparent in Sibley (2014). Although Pyle (1997) presents a wingtip metric for Chihuahuan (the relative lengths of primaries 5 and 9), no such measurement is given for Com-mon.

Tail ShapeWith the exception of voice, tail shape is probably the single char-

acter used most often by birders to identify ravens to species in Colo-rado (and elsewhere in the New World). In general, Chihuahuan Ravens have rounded tails and Common Ravens wedge-shaped tails. However, tail shape seems to be a factor associated with sex, with females of both species possibly being rounder-tailed than are males. Thus, as with overall size, male Chihuahuans and female Commons

Table 1. Chihuahuan and Common Raven measurements1. Measurements are in mm; sample sizes (where provided in source literature) are in parentheses.


may very well overlap in tail shape. Yes, those nearly diamond-shaped tails of large, long-tailed male Commons probably provide an excellent identification clue, but round tails do not do much for us. Unfortunately, Pyle (1997) did not provide a range of values of “wedged-ness” (r1-r6; the higher the value, the more wedge-shaped) for the subspecies found in Colorado, so the range provided in Table 1 includes all four North American subspecies. Because sinuatus is a medium-sized subspecies, the larger and smaller values of that range are probably not found in Colorado. Also, it is probably worth men-tioning that factors including how spread the tail is as well as the degree of molt and/or wear of the tail can impact one’s impression of tail shape.

Back-cover Photo, Part IIAre you ready to tackle the identification of this raven using the

above criteria? Size: With nothing in the picture other than raven and blue sky,

we cannot determine the bird’s overall size. Bill shape: With the bird’s bill being open, we cannot adequately

assess the depth of the bill, thus the ratio of length to depth cannot be determined. (There do seem to be some odd aspects of this bird’s bill, which are discussed below.)

Nasal-bristle length: Despite the low angle of the photo, we can see the extent of the nasal bristles, which appear to lay on about half the length of the top of the bill, so that character is not useful to identify this individual.

Color of the base of neck and breast feathers: There seem to be some gray bits in the bird’s neck/breast plumage, which might suggest Common Raven as the identification. However, this appearance is not due to ruffled feathers and exposure of the feather bases to the light (more on this below).

Throat shagginess: The throat is shadowed in the picture and no shagginess is evident (more on this below).

Wing length and shape: The wings seem fairly short and wide, at least to me, and the wingtip seems an odd combination of pointed [long distance between the tip of the outermost (p10) and longest primaries) and squared-off (p6-p8 being of the same length). Perhaps this feature points toward Chihuahuan (more on this below).

Tail shape: The tip of the tail is smoothly rounded, with no sug-gestion of a wedge shape, though the absolute tail length seems a bit long to my eye. This character may be a wash, or could lean toward Chihuahuan.


Ageing RavensI know…why would you want to? Well, as with gulls and many

other bird species, determining the bird’s age can instruct on the identification process. At least with ravens, we have to deal with only two age classes, adult and juvenile/immature (birds in their first plumage cycle; Leukering 2010). The pictured bird is readily aged as an immature by at least three features. 1) The gape and the roof of the mouth (the latter of which we can see well thanks to the open bill) are pale and contrast with the black of most of the outside of the bill. Adults lack such an obvious gape (and what they show is black) and have the roof of the mouth black. 2) The body shows a mix of feather generations, with scattered clumps of gray-brown neck, breast and belly feathers that are remnants of juvenile plumage. 3) The color of the primaries and secondaries are a grayish-brown that produces a strong contrast with the black formative (Leukering 2010) feathering of the wing linings.

Knowing that the picture was taken in July, and knowing that there has been extensive replacement of juvenile body plumage, but no replacement of flight feathers, we can determine that this bird was hatched this year and is, at best, a few months old. Additionally, because the bird is still wearing its juvenile flight feathers, we might want to consider any wing-shape characters to be suspect as wing shape in juveniles/immatures of many bird species differs from that of adults of the same species (e. g., many or most eagle species, most or all Buteo species, Little Gull).

Taking into account all of the above, I find that there are no strong clues to allow identification of this raven. Well, there is one, but un-less you looked ahead, you wouldn’t know that the photo was taken in northwestern Montana, about ten miles from the U.S. border with Canada. The location should nicely rule out Chihuahuan Raven.

While range-based identification may not be very satisfying, bird-ers use that criterion all the time. A silent wood-pewee seen in Utah is a Western, but seen in Virginia it’s Eastern. Yet as birders state all the time, “birds have wings” and the ability to show up where they are not “supposed” to be, so why is the pictured bird not documenta-tion for Montana’s first record of Chihuahuan Raven?

Despite the aforementioned poorly supported scattering of eBird reports of Chihuahuan Raven nearly the length and width of Colo-rado, the vast majority of reports of the species come from that part of the state where they are “supposed to be.” Colorado birding has the belief that, at least in the breeding season, Chihuahuan Ravens occupy the prairie, Common Ravens the foothills and mountains, with a bit of overlap on the prairies within a few miles of “suitable”


Common Raven habitat. This creates the situation in which ravens on the plains in summer are identified as Chihuahuans and those in the mountains and foothills as Commons, a circular-reasoning situ-ation if ever I saw one. Raise your hand if you have ever identified a distant summer raven on the plains as a Chihuahuan, despite the fact that you discerned no useful field characters. Did your hand join mine, which was wildly waving in the air? Why is it that we are will-ing to use range maps as the sole feature to identify individuals of some difficult groups, but not of other groups?

Consider this essay a plea for more thought and care in raven identification in the state, which should lead to more extensive use of the “raven sp.” category in field notebooks and in eBird.

ACKNOWLEDGMENTSI greatly appreciate discussion of raven bill morphology with and unpublished data on such from Peter Pyle. I also thank Steve Mlodinow for a thoughtful review of a previous draft of this essay.

liTerATure CiTedAiken, C. and E. Warren. 1914. Birds of El Paso County. Colorado College

Publ. General Series 74, Science Series No. 13. Colorado Springs, CO.Henshaw, H. W. 1875. Report on the ornithological collections made in por-

tions of Nevada, Utah, California, Colorado, New Mexico, and Arizona, during the years 1871, 1872, 1873, and 1874 in report upon geographical and geological explorations and surveys west of the one hundredth merid-ian, vol. 5. U. S. Government Printing Office, Washington, DC.

Leukering, T. 2010. Molt and plumage: A primer. Colorado Birds 44:135-142.

Nelson, D. L. 1998. Chihuahuan Raven. In Colorado Breeding Bird Atlas (H. E. Kingery, ed.), Colorado Bird Atlas Partnership and Colorado Divi-sion of Wildlife, Denver, CO.

Pieplow, N. 2014. Common vs. Chihuahuan Ravens. Earbirding.com (http://earbirding.com/blog/archives/4736). [Accessed 4 August 2015]

Pyle, P. 1997. Identification Guide to North American Birds, part I. Slate Creek Press, Bolinas, CA.

Sibley, D. A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.Sibley D. A. 2014. The Sibley Guide, 2nd ed. Alfred A. Knopf, New York.

Tony Leukering, [email protected]

Fig. 1 (back cover). Immature Common Raven, Toole Co., MT, 30 July 2015. Photo by Tony Leukering


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