bird conservation fall 2012 short

7/30/2019 Bird Conservation Fall 2012 Short

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he Magazine o American Bird Conservancy Fall 2BIRD CONSERVA ION


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2 bird conse rvation FaLL 2012

BIRD S EYE VIEW

COVER PHOTO: l Oregon Junco: Pat Hunt

Is Species Conservation Enough?

At one extreme, a conserva-tion skeptic might insist thatpreserving one type o birdrom each genus is su cient. At theother, passionate lovers o wildli emay not accept the loss o even oneindividual. A more typical birder

might nominate the species as thekey conservation level because theconcept o species is amiliar to us.

Science gets us closer to the answers,but it cannot draw the line: the purpose o science isto gather knowledge, not to make decisions or us.Furthermore, like li e itsel , the science o taxonomy isin a constant state o change. Baltimore and BullocksOrioles have been lumped into Northern Oriole andthen split again, all based on the most current scien-

ti c opinion. And with constant advances in genetics,even our understanding o relationships at the amily and order levels is being challenged.

And yet decisions need to be made. Almost every day we hear about a new threat to a vaguely de ned popula-tion o birds: Recently, or example, I learned that only one stronghold or the American Dipper remains east o the Rockies, in a single creek in the Black Hills o SouthDakota. Scientists studying this bird have proclaimed ita new species, but others arent so sure. Still others arecalling or this bird to be protected, whether it is a new species or not.

Variations on that kind o argument are now taking place all over the United States. Are the genetically andmorphologically identical tree- and ground-nesting Marbled Murrelets each worthy o conservation? Whatis lost i Waynes Warbler, a distinct population o thecommon, boreal orest-nesting Black-throated Green

Warbler that nests in cypress bottoms o the Carolinas,

becomes extinct? Do we care aboutthe continuation o these evolution-ary processes, or do we take a passon preserving them because thesebirds are not su ciently unique?

When in doubt about whether totake conservation action, I all back on the precautionary principle,

which says, in essence, that whenuncertain about the potential harm-ul efect o an action, the prudent

u h . o , al L p l wrote, Save all o the pieces.

I say, save the Black Hills Dipper regardless o whichtaxonomic opinion prevails; and while we are at it, weought to save Waynes Warbler, the rhododendron-dwelling Swainsons Warbler, and the tree-nesting Marbled Murrelet too. Sometimes theres no time to

wait or taxonomic certainty. Tats the kind o ddling that let Rome burn.

In other words, is species conservation su cient? Webelieve the answer is no, and in this issue o Bird Conservationwe explain why. And it is critical or uturegenerations that we get it right.

ABCs Mike Parr deserves credit or compiling thecomplete checklist o birds and their conservation rank-ings (also available at www.abcbirds.org/checklist). ABC

would also like to thank Chuck Hunter, Arvind Panjabi,and David Sibley or their valuable contributions to thisissue o Bird Conservation.

George Fenwick President, American Bird Conservancy

How should we as conservationists decide which birds deserve protection? Where swe draw the line that tells us which groups o birds are unique enough to merit sav

l American Dipper: USFWS


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bird cons ervation FaLL 2012 7

NorthernFlicker

l Red-shafted (western) l Yellow-shafted (eastern)

ConservingTotal Bird

Diversity inthe United

States

For bird conservationists, the coin o the realm has almost always been the species. Eforts to protect bird div

measured by species count, and eforts to prevent extinctionwith some exceptions ocus at the species lev

natural diversity is almost in nitely complex, and so our species-based system o conservation priority-setting

the vast array o diferences that separate birds o the same species. Tis diversity cannot be protected until it h

been recognized and ranked. ABC believes that bird conservation should address all diversity rom the specie

population level.

At the next level beyond species are distinctive geographicorms, or subspecies. Well-known examples include

Yellow-sha ted and Red-sha ted Northern Flickers, andBronzed and Purple orms o the Common Grackle.But any good biologist will tell you that the diferencesbetween birds o a eather are more complex thanmeet the eyeand much more must be done to head of

looming threats to birds beyond the species, and evensubspecies, level.

For example, some bird species may not have recognizedsubspecies, but still have populations with separate ranges,

such as eastern and western Barrows Goldeneyes, andeastern and western Golden Eagles. Other species havepopulations that occupy separate and distinct ecologicalniches, but are otherwise identical or example, Swain-sons Warblers that nest in Appalachian orests instead o bottomland swamps. Beyond this, there are species thathave distinctive color morphs such as some owls, nightjars,

jaegers, and raptors (some morphs are regionally concen-trated, others are not); and even hybrid populations thatoccupy speci c geographies. Myrtle and Audubons War-blers have such a zone in the Canadian Rockies. In act,

l Audubons Warbler: Robert Royse


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TYPES OF BIRD DIVERSITYThe deeper one delves into bird diversity, the more complexand interesting things become. There are a variety of waysto divide birds into distinct groups or populations, but ABCis focusing on the following:

Species variously defined, but generally meaning adistinctive form or group of closely related forms that is (or are)

reproductively isolated from other such forms or groupings.Subspecies a regional variant within a species that is distinctivein form, but is not completely isolated or highly differentiated while these variants have different breeding ranges from eachother, they may mix outside the nesting season.

Cline a gradient of forms within a species that may notcleave easily into clear subspecies. In some cases, whileextreme geographic forms of a species may be quitedistinctive (e.g., eastern and western forms of the HairyWoodpecker), it can be hard or impossible to identifyprecise locations along the gradient where divergence tothe subspecies level takes place. For now, however, ABCstill views subspecies division as the most practical means

of categorizing and creating conservation rankings for formswithin clinal species.

Population Segment a geographically separate populationof a species or subspecies that has limited gene flow to othersimilar populations due to its isolation, but is otherwisegenerally indistinguishable (e.g., the eastern population of the Golden Eagle).

Habitype ABC has created this term to describe a groupof individuals within a species that occupies an ecologicallyunique niche e.g., habitat preference, timing of breeding,or a specific nesting strategy but that is otherwise identicalto other individuals within the species (e.g., tree-nesting andground-nesting Marbled Murrelets).

Morph a color variant within a species or population.These color variations can crop up seemingly randomly withno geographic concentration based on gene dominance,but ABC is most interested in those that have regionalconcentrations (e.g., dark morph of the Broad-winged Hawk).

Hybrid a cross between two species that may or may notbe regionally concentrated (e.g., hybrids between Myrtleand Audubons Warblers).

there are multiple, complex gradations o orms that insome birds are sharply de ned, and in others blend romone to another across the landscape in clines rom east to

west or north to south.

While the U.S. Endangered Species Act (ESA) includessubspecies as well as Distinct Population Segments (seearticle page 22), the very word sub species implies a levelo in eriority that may afect the way these populationsare viewed. Since so much conservation happens locally orregionally, most projects end up being directed at popula-tions rather than at entire species. o maximize these e -orts to conserve bird diversity, it would be better i actions

were applied in a coordinated, strategic manner to protectall populations and ecological types.

How then can we unravel this vastly complex world o ge-netics and ecology to devise a national approach that truly addresses the conservation o all Americas bird diversity?

o draw conservation attention to the broader array

o diferences among birds, ABC has created a list or the50 United States and U.S. territories that provides con-servation rankings or both species and subspecies basedon the standard bird conservation scoring system used by Partners in Flight. Tis list provides the critical rst step inhelping set priorities or those birds most in need o help,regardless o their current status as a species or subspecies.

Te list also identi es important geographic population seg-ments, populations restricted to particular ecological niches,and some morphs and hybrids. Te ull list (along with itsmethodology and bibliography) is available on ABCs web-

site (see www.abcbirds.org/checklist). A checklist version(including just orms that can be identi ed in the eld) isincluded with this issue o Bird Conservation. Tis checklistincludes color-coded conservation rankings rom Secure(green) through Potential Concern (yellow), to Vulnerable(orange), and At-Risk (red). David Sibleys excellent onlineresource on identi able subspecies helped us select whichsubspecies should be included. We would also like to thank David or the use o his superb illustrations or this issue o Bird Conservationlook out or the new edition o Davidseld guide coming soon.

Tis ABC list puts all birds on the radar screen orconservation regardless o taxonomic decisions so that

we can better avoid birds alling through the cracks o conservation action. We are also pleased to include thebirds o Hawai'i in the list, since our 50th state is home tomany o Americas most threatened birds.

Te new ABC list also provides the scienti c and conceptualbasis or the articles and approaches detailed in this issue o Bird Conservationmagazine. We look orward to much spir-ited and constructive debate on how we can work togetherto conserve the ull diversity o Americas birds.

Hairy Woodpecker cline

l (Duller - Pacifc)l (Whiter-winged

- eastern)l (Darker-winged

- interior)


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9bird cons ervation FaLL 2012

We anticipate that some o the birds to which we have as-signed ull species status (as opposed to subspecies) in the

ABC list may spark debate. However, it appears likely thatas taxonomy advances, ar more bird species will ultimately be recognized than is the case today. We welcome discussionon these issues, and we are particularly interested in how quantitative thresholds can be set that enable taxonomists,conservationists, and birders to agree on and operate of o a single global species and subspecies list. More details on ourbasis or making these decisions appear on the ABC website.

Species to Populations

While the primary ocus o ABCs new list is on providing conservation ranks or species and subspecies, we also notethose species within which variation is more gradual andthose with disjunct regional population segments thatmay warrant conservation attention.

Subspecies can also requently be aggregated into regionalgroups that show similar characteristics. While thesegroups may appear quite distinct rom each other, the sub-species within them may be separable only by subtle char-acters such as bill measurements and plumage tones. Tesegroups can be de ned in various ways, and ABC identi esseveral in the enclosed checklist based on orms that show common eld identi cation characters. A more detailedtaxonomy o these groups is provided in the online versiono the checklist.

Te concept o population segments is currently knownprimarily in relation to the U.S. Endangered Species Act.In this context, a Distinct Population Segment (DPS)is a population that is both discrete within, and signi -cant to, a species, although its application is requently determined by legal interpretation. While this is similar to

ABCs de nition o a population segment, a DPS cannotbe designated without meeting the Acts standards or list-ing, and its designation may be subject to both biologicaland legal interpretation. In contrast, ABCs goal is to listall population segments so their conservation status can bemonitored and addressed prior to the need or listing.

Te concepts o morphs and hybrids, though well under-stood and accepted, are in requently considered in conser-vation circles, and ABCs habitype division is new.

Morphs Around ty American bird species have some color vari-ants that can be regarded as morphs, and these speciescome rom a surprisingly wide range o amilies. Some o these morphs occur within species that are already knownto be o conservation concern, such as the Pink- ootedShearwater and Reddish Egret.

While it is unnecessary to direct conservation to speci ccolor variants that occur randomly across populations,some morphs are geographically concentrated such asthe range-restricted dark morph o the Broad-wingedHawk that nests in Alberta, Canada and some o thesemay be worthy o conservation attention.

T k m ph f h L b , l k w c y L b , w l g ly uoronto, Canada, although records came rom as ar a eldas Florida and Michigan. Sadly, there have been no con-rmed North American reports o this rather spectacularorm o the species or several decades.

As long as morphs that are geographically concentratedand potentially o conservation concern remain of theconservation radar screen, there is less chance that the bird

l Fox Sparrow: Robert Royse l Sooty Sparrow: Robert Royse

The four distinctive forms of the Fox Sparrow are becoming recognized as separate species. The eastern (left) and Pacific (right) forms are pictured.


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community will be aware o or able to respond to changesin their populations or threat levels. While we recognizethat both conservation need and opportunity will be rare,

we hope the new ABC list will be a rst step towardsassembling better data on the status and distributions o these intriguing birds.

HybridsHybrids the ofspring o pairings between diferent spe-

cies are o ten overlooked by the bird conservation com-munity. When conservationists think about hybrids it ismost o ten in the context o preventing them especially those that bene t rom human activities at the expenseo rarer species whose populations could be genetically swamped. Well-known examples include Barred Owls(that are spreading northwest due to human-caused habi-tat ragmentation) interbreeding with Spotted Owls, andMallards interbreeding with Hawaiian or Black Ducks.

Many birds occasionally naturally hybridize in the wild,but we generally have little in ormation on what happens

to the ofspring o these pairings. Tere are a ew species,though, such as Myrtle and Audubons Warblers, that hy-bridize success ully on a regular basis, and several that havestable hybrid zones where intermediate populations canreliably be ound. Another regularly occurring, though lessgeographically concentrated, set o hybrids are the variouscombinations between Blue-winged and Golden-winged

Warblers (and between them and their hybrid ofspring)h g h u g L w W l the subtly beauti ul Brewsters Warbler.

Many o us consider hybrids to be unwelcome and a

potential threat to genetically pure bird species. Hy-brid gulls along the Paci c Coast in particular requently draw the wrath o birders, because they are increasingly abundant (thanks to human-created land lls and ofaldiscarded rom shing boats), cannot clearly be identi edto species, and perhaps at a more undamental level, seemto represent a orm o genetic pollution that decades o popular science and science ction have taught us to shun.

Why should we view natural hybridization negatively

though? Some o these hybrid populations may be wor-thy o conservation attention, particularly those that aregeographically concentrated.I birds in one o these hybrid zones came under threat,

what should our reaction be? Should we be pleased thathybridization was going to be reduced, or should we act toprotect the population as a valid component o our overallavian diversity? Birders may well be enticed by the idea o

g u g L w W l , u -tionists have yet to determine i and how we value hybridsrom a conservation standpoint.

Habitypes ABC coined the term habitypes to re er to birds thathave unique ecologies, but that are not otherwise distinc-

tive rom related popula-tions. wo classic ex-amples that we o ten re erto are Swainsons Warblersthat nest in Appalachianrhododendron thickets

instead o bottomlandhardwood swamps, andMarbled Murrelets that nest high in trees in coastal orestso the Paci c Northwest rather than among Alaskan screeslopes.

Other examples include Common erns that nest in resh- water rather than marine areas; and oak and cottonwood,

h h f - g, L w W p k . e ho these habitypes is ecologically unique and represents anirreplaceable and ascinating element o avian diversity, yet

was not previously distinguished or conservation purposes

rom other populations o its species in any ormal way. ABC believes that these, and other such habitypes, haveconservation value, and we identi y some o them in thenotes section o our list on the website. Beyond habitypes,other measures o bird diversity include regional variationsin song type and molt timing. Further study may revealeven more cryptic patterns that have conservation signi -cance. We look orward to hearing o additional examplesthat can be added to the list.

l Blue-wingedWarbler

l BrewstersWarbler

l LawrencesWarbler

l Golden-wingedWarbler

Blue-winged and Golden-winged Warblers and their hybrids. Do the hybrids merit conservation attention?

l SwainsonsWarbler

HYBRIDS


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CENTERS OFDIVERSIFICATION

SAN FRANCISCOBAY, COASTAL &SOUTHERN CA

Aleutian andPribilof Islands

CALIFORNIAISLANDS

ROCKIES

SIERRAS

l The White-winged Juncohas a breeding range extendingfrom the northern Rockies intoNebraska and the Black Hills.

l The various forms of the HermitThrush are more different in

appearance than the already-splitGray-cheeked and Bicknells Thrushes.

The recent split of Xantuss Murrelet into twospecies, the l Scrippss (top) and l Guadalupe(bottom) Murrelets, shows how cryptic species

can often remain hidden in plain sight.

l The McKays Buntinghas a very small breeding

population that isvulnerable to invasive

species incursions.

l The distinctive

Rocky Mountain formof the Gray Jay (right)has a paler head than

its Pacific (left) andnorthern counterparts.

l Clapper Rail(Intermediate/darker -

S. & Gulf)


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15bird cons ervation FaLL 2012

SOUTHFLORIDA

APPALACHIANS

TH TExAS ANDGULF COAST

ertain parts of the United States are centers for bird diversification; these are the ecological engine roomsof American bird evolution.This map highlights areas of isolated habitat where bird populations have becomegenetically stranded due to topographical and ecological conditions. If this isolation is significant and long-

lasting enough, it can cause bird populations to diverge so they begin to consistently differ from their close relativesin plumage and other characteristics. Ultimately, todays subspecies can become tomorrows full bird species.

ATLANTICCOAST

l The more rufous easternBewicks Wren has all but

disappeared. It once rangedfrom Arkansas to Pennsylvania.

l Bicknells Thrush was split fromGray-cheeked in 1998. It nests inmountain and northern coastal

areas and winters primarily on theisland of Hispaniola.

l Appalachian Black-throatedBlue Warblers have streakedmantles and are sometimesrecognized as a subspecies.

l The grayish WorthingtonsMarsh Wren has been undergo-ing a decline in Florida, but likemany subspecies, range-wide

trend data are still lacking.

l The darker Florida Burrow-ing Owl is declining, exceptin coastal areas where it has

adapted somewhat to thehuman environment.

l The Gulf Coast Seaside Sparrowis brighter than the Atlantic form andhas a slightly different song pattern.

Denotes centers of diversification. Map depicts some species and subspecies examples.


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The lists on this and the following pages show somehighlights from ABCs new species and subspeciesconservation analysis (see www.abcbirds.org/checklist for full details). We hope that these will be thought-

provoking, and will lead to more conservation actionfor the featured birds.

Gunnison Sage-GrouseSitka Sooty Grouse (ssp)Lesser Prairie-Chicken

Black-capped PetrelPink-footed ShearwaterAshy Storm-PetrelHawaiian Storm-PetrelReddish EgretYellow RailBlack Rail (both ssp)Gulf Snowy Plover (ssp)

Alaskan Marbled Godwit (ssp)Eastern Red Knot (ssp)Kittlitzs Murrelet

Guadalupe MurreletScripps's MurreletCraveris MurreletRed-crowned Parrot

S. CA Olive-sided Flycatcher (ssp)S. FL & Is. Loggerhead Shrikes (ssp)S. CA Pinyon Jay (ssp)

Kauai 'ElepaioHawaii 'ElepaioEastern Bewicks Wren (ssp)Bicknells ThrushSF Bay Common Yellowthroat (ssp)Mangrove Prairie Warbler (ssp)Arizona Grasshopper Sparrow (ssp)Eastern Painted Bunting (ssp)Maui 'Alauahio (Maui Creeper)

PRIORITY LISTS

l Gunnison Sage-Grouse: Noppadol Paothong

At-Risk - 9%

Secure - 15%

Vulnerable - 30%

PotentialConcern - 46%

Most At-RiskHere are the most At-Risk birds not currently listed under the Endangered Species Act (ESA),including candidates

Proportion of U.S. birds in each risk category*

*See website at www.abcbirds.org/checklist for category definitions.


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25bird conse rvation FaLL 2012

Puerto Rico (PR)PR Broad-winged Hawk (ssp)PR Plain Pigeon (ssp)PR Common Ground-Dove* (ssp)Puerto Rican ParrotPuerto Rican NightjarCaribbean Black Swift (ssp)*

Puerto Rican Tody*White-necked CrowElfin-woods Warbler*PR Grasshopper Sparrow* (ssp)Yellow-shouldered BlackbirdPuerto Rican Oriole*

Guam and Northern Marianas(NMA)

NMA Micronesian Scrubfowl (ssp)Guam RailGuam Common Moorhen (ssp)Mariana SwiftletGuam Micronesian Kingfisher (ssp)

Mariana CrowTinian Monarch*Nightingale Reed WarblerRota Bridled White-EyeGolden White-Eye*Guam Micronesian Starling* (ssp)

American SamoaFriendly Ground-Dove

Territories

l Elfin-woods Warbler: Mike Morel, USFWS

Analysis for the lists on these pages (and

the following) pertains to non-accidental native birds in the 50 U.S. states and territories that have more than 5%of their global population occurring here. Those species that are potentially extinct are excluded. Note that the list on the following page uses data fromthe Breeding Bird Survey. Subspeciesdenoted by (ssp).

At-Risk species and subspecies for U.S. territories.Those marked* are currently neither listed nor candidates for listing under the ESA.

While this issue of Bird Conservation focuses mostly on the 50 U.S. states, ABCs new analysis alsocovers U.S. territories in the Caribbean and Pacific. You can review a full list of birds that occur in theseterritories with their conservation rankings on the website at www.abcbirds.org/checklist.

l Yellow-shouldered Blackbird: Mike Morel, USFWS

l Puerto Rican Parrot: Pablo Torres, USFWS


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26 bi d i F LL 2012

l American Wigeon

l Northern Pintail

l Horned Grebel King Rail

l Lesser Yellowlegs

l Franklins Gull

l Black-billed Cuckoo

l Black Swift

l Rufous Hummingbird

l Allens Hummingbird

lOlive-sided Flycatcher

l Horned Lark

l Bank Swallow

l Varied Thrush

Fastest Declining Migrants

l Chestnut-collared Longspur

l McCowns Longspur

l Golden-winged Warbler

l Cape May Warbler

l Cerulean Warbler

l Palm Warbler

l Wilsons Warblerl Lark Bunting

l Grasshopper Sparrow

l Bairds Sparrow

l Rusty Blackbird

l Grasshopper Sparrow: Robert Royse

Note that population trend is only one factor in assessing risk,so some species with large ranges and populations (such as thePalm Warbler) can currently be regarded as Secure, even thoughthey are declining. This list addresses full species only. For sub-species see the online list at www.abcbirds.org/checklist.

bird conservation fall 2012 short

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