Iron County Loon Project

“Practicum in Loon and Lake Ecology and Management”

Final Report 2015

Background

For the more than 20 years, the Wisconsin Department of Natural Resources (WDNR)

Bureau of Integrated Science Services has conducted research on the potential impacts of

mercury on loon populations in northeastern Wisconsin. This work has examines causes

of loon productivity decline on a number of lakes in Iron, Vilas, Oneida and Forest

Counties. Results of this study are pending, but initial findings suggest that loons nesting

on high mercury, low pH lakes have reduced chick production and survival. In addition,

this study has looked at the impact of habitat loss on loon populations. One finding of

this work is that loons living on small lakes where there are no islands have reduced

production of chicks. To combat this decline in nest success, artificial nesting platforms

have been placed on lakes where loons have had trouble successfully reproducing,

resulting in chick production doubling. The WDNR is considering ways to manage and

maintain platforms on target lakes.

The WDNR approached Iron County with the idea of piloting a citizen-monitoring

program for platforms. The concept for the Practicum in Loon and Lake Ecology came

out of this discussion, with Hurley and Mercer students involved in a pilot during the

spring and summer of 1999. Students constructed nesting platforms; selected study lakes

based on water quality and habitat features, and placed and monitored the platforms in

spring and summer. To date, this program has been monitoring lakes health and loon

production for over 16 years. The students’ work has resulted in many successfully

hatched loon chicks from the artificial platforms that they have constructed and place out

for loons to use in Iron County, WI.

The physical data for each of the lakes involved in the project are shown in Table 1.

Lakes varied in public ownership from nearly 100% to none. All of the lakes are either

seepage or drainage lakes within the Mississippi River and Lake Superior watershed.

Shoreline development varies, with students ranking two lakes as low percentage of

shoreline developed and the other three medium or high leveled developments. It should

be noted that none of the lakes are as highly developed as lakes found in more southerly

regions of the state and student rankings on development are comparative only in Iron

County.

Table 1. Physical Lake data Iron County, WI.

Lake Name Estimated

% Public

Ownership

Acreage Max

Depth

Watershed

Basin

Sub Watershed Lake

type

% Shoreline

Developed

Pardee 0 206 27 Lake Superior Montreal River Drainage Medium

Fox 20 46 23 Mississippi Turtle Flambeau Seepage Low

Deer 100 32.5 18 Mississippi Turtle Flambeau Seepage Low

Grand Portage 20 144 31 Mississippi Turtle Flambeau Drainage Medium/High

Hewitt 1 79 89 Mississippi Turtle Flambeau Drainage Low-Medium

Gile 25 3138 25 Lake Superior Montreal River Drainage Medium

Goals

Provide Iron County teachers with cost effective and practical assistance in meeting

curriculum needs in environmental education, water quality, aquatic habitats and

wildlife management

Increase students understanding and appreciation of water resources, aquatic and

riparian habitats, loon ecology, and issues relating to management of natural

resources

Increase outdoor skills of Iron County school students

Assist Iron County Forest, the LCD Land and Water Resource Plan and WDNR in

meeting education priorities

Test methods for increasing loon chick production on Iron County Lakes

Objectives for Student Learning

Students will learn methods for studying water quality and will test water chemistry

on study lakes

Students will learn about the natural history, ecology and management of common

loons

Students will be able to explain current issues relating to loon protection and habitat

management

Students will learn methods for sampling invertebrates

Students will construct artificial nesting platforms for common loons

Students will assess lake habitats and historical loon use and will select locations for

platforms

Students will place platforms on lakes and will monitor loon presence, nesting, and

chick production

Students will learn computer data management and analysis and presentation skills

Methods

In the 2015 field session, 15 high

school students from Hurley and

9 eighth grade students from

Mercer participated in the

program. Throughout the years

students constructed artificial

nesting platforms in shop classes.

Each platform followed the

construction model developed by

the WDNR. Students received a

training session on loon ecology,

habitat needs and threats to loon

nesting success such as lakes with high acidity and the presence of heavy metals.

Students then selected lakes for platform placement and platforms were placed on Fox,

Deer, and Grand portage Lake with Mercer in mid-May and on Pardee, Hewitt, and the

Gile with Hurley. Little Pike Lake, near Mercer, was also a project lake, however, due to

time restrictions lake property owners maintained the platform and conducted water PH,

secchi and dissolved oxygen tests. In addition to platform study lakes the project

observed Pine Lake and the Gile Flowage for nesting and chick production. This year

had a normal ice off date.

During the spring field trip, in addition to placing artificial loon nesting platforms,

students collected data on watershed size and characteristics, dissolved oxygen,

temperature, pH, water clarity, and conducted a survey for marcro-invertebrates. They

used field chemistry test kits, secchi disc, topographic maps and water surface inventory

books to help analyze the lakes physical and chemical makeup. Data was recorded on a

“lake profile data sheet”. Loon presence and behavior was also recorded on a separate

loon presence data sheet. Six artificial loon platforms were placed this year. Return trips

to the lakes were conducted in June, July and August. Water quality, water clarity and

marcro-invertebrate tests were repeated at return visits. In addition, shoreline buffer

transects (June) and aquatic vegetation transects (July) were completed on subsequent

visits. Loon presence, nesting status, chick production and chick survival and the

presence or absence of predators were also noted at each visit. This year the students took

on a new challenge and placed trail cameras on both natural and artificial nest platforms

to record nesting status and any presence of predators or other nesting issues that may

impact nesting success.

Results and Discussion

Loon Production Loons are known to utilize natural and artificial nests on both developed and

undeveloped lakes. Out of six platforms placed, loons utilized five of the platforms. The

Gile Flowage sub-pond was not used this year. Pardee, Fox, Deer, Grand portage, and

Hewitt Lake platforms were used but only produced a total of two chicks. Grand portage

was the only lake that successfully produced chicks from the platform however lake

residence witnessed eagles killing both chicks. The Gile Flowage sub-pond pair hatched

two chicks on the first nest attempt and Hewitt Lake loons started out on the platform

however was predated on and re-nested naturally and produced one chick. For Hewitt

this was the first natural nest success in many years. Egg shell fragments were observed

on the Hewitt Lake nest platform suggesting predation during the first nest attempt. Out

of a total possibility of 12 chicks on both natural and artificial nests, two chicks hatched

off of the platforms and three chicks hatched naturally, making chick production 12%

successful on platforms and 20% successful naturally. Loons on Little Pike nested

naturally however failed and did not produce a

chick. In conclusion, the results from this

year’s loon research were quite unusual

compared to past data. With the normal ice out

conditions, lack of black flies, and five out of

six nest platform used, we were expecting a

higher chick production. Camera work on

artificial nest platforms will continue next year

in hopes of understanding why platforms nest

are failing.

Pardee Lake Nest

Nest Camera Results: Predators and other disturbances

This year we placed three trail cameras at loon

nest sites. All three cameras were attached to

artificial nest platforms from Mid-May through

the nesting season. The results from the camera

study were very interesting and educational. The

Fox Lake camera showed nest building,

copulation and egg laying however the nest was

later abandon. Hewitt Lake also showed nest

building, copulation, and egg laying however the

nest was predated on and the batteries in the camera had died before the event resulting in

no photos of any predators. During the first two weeks at the Pardee Lake camera

muskrat and Canada geese appeared at the nest cup but later the loons nested, laid two

eggs and also abandoned the nest. The camera also documented both male and female

sharing incubation and egg turning.

Nest abandonment occurs time to time on both developed and undeveloped lakes and on

both natural and artificial substrates. Lakes with successful nesting ranged from slightly

acidic to basic, and water clarity varied. Platforms were most successful where there was

a history of previous failed nest attempts and platforms were placed directly next to the

historical site. Platforms placed in seemingly good locations, but not directly adjacent to

the natural site were not used. On lakes where platforms were successful, in-depth

information from landowners and researchers was utilized in selecting platform locations.

Loons are known to use the same nesting sites year after year, even selecting the same

nest cup location from time to time. This suggests that in future years, platforms be

located as close to historical sites as possible.

Natural Artificial

(Deer Lake Natural Nest) (Hewitt Lake Platform)

Table 2. Loon nesting success 2015

Lake Name Nesting (y/n) # Chicks produced # Chicks at late

summer visit

Pardee Y, Platform / natural 0 0

Fox Y, Platform, 0 0

Grand Portage Y, Platform 2 0

Deer Y, Natural, Abandon 0 0

Little Pike Y, Natural, Predated 0 0

Gile Flowage Y, Natural 2 2

Hewitt Y, Natural 1 1

Total 7 Lakes 5 3

0 0 0 0

2

4

0

3

00

1

2

3

4

5

Cry

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Deer

Fo

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Lit

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Pin

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Hew

itt

# o

f C

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ks

Loon Chick Production (without platforms) 1999-2015

02

5

19 19

0 0 0

4

0

2

4

6

8

10

12

14

16

18

20

Cry

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Deer

Fox

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Pard

ee

Gile

Flo

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Little

Pik

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Pin

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Hew

itt

# O

F C

HIC

KS

Loon Chick Production

(with platforms) 1999-2015

Figure 1. The below charts represent chick production since the project begun in

1999-2015.

Water quality

Students collected the following water quality

measurements at each of the three visits: dissolved

oxygen, pH, water clarity and surface temperature. In

addition, students collected samples of

macroinvertebrates at each visit and marcophytes on

the third visits as indicator of water quality. Water

quality reading help give an overall estimation of

aquatic water quality. Water quality readings help give

an overall estimation of aquatic ecosystem health, and

therefore, the suitability of a water body for loon

nesting. Water quality on study lakes is summarized

on Table 4 and all samples were taken near shore.

Dissolved Oxygen:

Dissolved oxygen (DO) is a factor in loon nesting success due to its effect on their main

forage base, the fish and macroinvertebrate community. Most fish prefer DO reading of

7-9 mg/L for optimal survival, and most will cease to exist in less than 3mg/L.

Table 3. Dissolved oxygen in loon study lakes 2015, Iron County, WI.

Analysis:

Dissolved oxygen readings were suitable for nesting loons on each of the study lakes

ranging from 7.0 at Pardee Lake to 10.2 also on Pardee Lake. Interestingly, Pardee Lake

is the only lake with a range of 3.2 and also is the most diverse lake with aquatic plants.

Figure 2. Dissolved Oxygen in loon study lakes in 2015, Iron County, WI.

Dissolved Oxygen

Reading 2015

Lake Name

Dissolved

Oxygen

(mg/L)

Average DO (3

visits)

Dissolved

Oxygen (Min-

Max)

Range Suitable for loons

nesting? Y/N

Fox 9.4 Total: 25.1 Min: 8.0 Range: 1.4 Yes

7.75

8 Average: 8.3 Max: 9.4

Deer 7.8 Total: 23.6 Min: 7.8 Range: 0.2 Yes

7.8

8 Average: 7.86 Max: 8.0 Grand

Portage 8.98 Total: 25.6 Min: 8.0 Range: 0.98 Yes

8.71

8 Average: 8.56 Max: 8.98

Pardee 10.22 Total: 25.5 Min: 7.0 Range: 3.2 Yes

8.34

7 Average: 8.56 Max: 10.2 Hewitt 9.24 Total: 26.2 Min: 8.42 Range: 0.82 Yes

8.56

8.42 Average: 8.74 Max: 9.24

0

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Fox Deer Grand Portage Pardee Hewitt

Disolved Oxygen 2015

Lake Name Visits Secchi (ft) Average Secchi (3 visits) Min - Max Range Suitablity for Loons Percent chance of success1st visit: 3 Total: 9.2

2nd

visit: 4.2 Min: 2 Range: 2.2 Poor <20%3rd visits: 2Average: 3 Average: 3.0 Max: 4.2

1st visit: 6 Total:18.25 Min: 5.25 Range: 1.75 Good 40%2

nd visit: 7

3rd

visits 5.25Average: 6 Average: 6.0 Max: 7.01st visit: 5.5 Total:22 Min: 5.5 Range: 3.5 Good 40%2

nd visit: 7.5

3rd visits 9Average: 7.3 Average: 7.3 Max: 9.01

st visit: 6 Total:23.5 Min: 6 Range: 4.0 Good 40%

2nd visit: 103

rd visits 7.5

Average: 7.8 Average: 7.8 Max: 101st visit: 17 Total:51 Min: 17 Range: 0.0 Great 80%2

nd visit: 17

3rd visits 17Average: 17 Average: 17.0 Max: 17

Fox

Deer

Grand Portage

Pardee

Hewitt

Waters Clarity:

Because loons are sight feeders, water clarity is of the utmost importance for nesting

success. High clarity readings mean ease of finding and capturing food for themselves

and for feeding and training chicks, thus making the lakes with higher clarity more likely

to support successful loon reproduction and raring.

Table 4. Water clarity (Secchi disc) in 2015 in loon study lakes, Iron County, WI.

Analysis: Hewitt Lake had the highest water clarity reading with a Maximum of 17 feet,

an average of 17.0 feet and was successful hatching a chick. Fox Lake once again had

the lowest with an average low of 3.0. Pardee Lake was the most variable with a

difference of 4.0 feet from the 1st to 3rd visits. For reasons unknown to us Deer Lake’s

clarity has improved several feet over the last 4 years and Fox Lake has decreased. Both

are seepage Lakes and about the same size. Fox Lake has some minor development but

shouldn’t be a major factor.

0

1

2

3

4

5

6

7

8

9

2000 2002 2004 2006 2008 2010 2012 2014 2016

Feet

Years

Fox Lake Secchi 2002-2015.

Figure 3. Water Clarity (Secchi disc) in 2015 in loon study lakes, Iron County, WI.

34.2

2 3

6 75.25 6 5.5

7.59

7.36

107.5 7.8

17 17 17 17

0

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Fox Deer Grand Portage Pardee Hewitt

Fee

t

Lake and Visit

Water Clarity 2015

Acidity (pH):

Northern lakes are especially acidic due to atmospheric deposition and from tannins from

pine trees and bogs. High acidity makes mercury and other heavy metals more readily

absorbed into the flesh of animals. Fish pick up these toxins and loons eat the fish.

Mercury is metabolized in the system of loons and can cause central nervous system

damage and affect their eyesight. In addition, high acidity (low pH), correlates with less

marcroinvertabrates in the system, resulting in less food for loon chicks. Therefore, the

optimal pH range for loon production is from 6-8.5 (around neutral).

Table 5. Acidity (pH) in 2015 loon study lakes, Iron County, WI.

Figure 4. Acidity (pH) in 2013 loon study lakes, Iron County, WI.

Shoreline Buffer and Aquatic Plant Survey

Lake Name Acidity (pH) Average pH

PH reading

Min - Max Range PH Suitability for loons:

(Total /3)

(min-max) Critical <4.3,

Suboptimal 4.4-6,

Optimal 6-8.5

Fox 6.8 Total: 20.8 Min: 6.8 Range: .13 Optimal

7

7 Average: 6.93 Max: 6.93

Deer 6.93 Total: 19.4 Min: 6.0 Range: .9 Slightly Optimal

6.5

6 Average: 6.4 Max: 6.9

Grand Portage 6.3 Total: 21.75 Min: 6.3

Range:

1.45 Optimal

7.7

7.75 Average: 7.53 Max: 7.75

Pardee 7.7 Total: 23.2 Min: 7.5 Range: 1.5 Optimal

8

7.5 Average: 7.7 Max: 8.0

Hewitt 6.25 Total: 19.25 Min: 6.25 Range: .25 Slightly Optimal

6.5

6.5 Average: 6.41 Max: 6.5

Shoreline buffer strips and aquatic plant transects were

conducted on all 5 lakes during the third visit. In

general, this data was taken as a general indication of

the lake health and the ability of a shoreline to provide a

substantial buffer for pollutants, and other toxins

entering the water body. Shoreline buffers also provide

habitat for fish and macroinvertebrates which loons feed

on. Because shoreline data were collected for

convenience sake at our lake access points which were

human-impacted homes and boat landings, the data

were naturally skewed, offering only a snapshot of

shoreline status, not an overall indication of buffer zone

health. We used this information as a foundation of a

discussion with the students about the importance of retaining natural buffer zones and

the effects that altering shoreline areas can have on lake health and loon reproduction. In

general, our data show less developed lakes had more complete and healthy shorelines,

which aligns with previous WDNR research that found that development of shorelines

significantly reduces the shrub layer and amount of dead and down woody debris.

Table 6. Shoreline buffer transects (Nearshore) in 2015 loon study lakes, Iron County, WI.

Table 7. Littoral zone macrophyte transect (aquatic plant survey) in 2015 loon study lakes,

Iron County, WI.

Lake Name Average %

Understory Cover

Average %Shrub

Cover

Average %

Canopy

% Woody Debris

Fox 51 20.5 24 Medium

Deer 57 33 31.5 Medium

Grand Portage 67.8 4.5 44.4 Low

Pardee 61.5 3 66 Medium

Hewitt 28.7 8.1 27.7 Medium

Lake Name Average % Cover Substrate % Woody Debris

Fox 29 Muck Medium

Deer 1 Muck Medium

Grand Portage 100 Sand and muck Low

Pardee 60 Sand and gravel Low

Hewitt 2.89 Sand and muck High

Conclusions and Discussions

Students planned, constructed, and monitored loon nesting on 7 lakes in Iron County. 5

of the 6 platform lakes were used by loons however only 1 produced chicks. This is

probably our lowest success rate since the start of the project. Several factors, weather

and a late ice off, may have played a large role in the poor success. Hewett Lake was a

new addition to the project and with continued platform placement; we feel that this lake

has a lot of potential. If ice conditions and extreme weather changes continue in the

Northwood’s, loons may be impacted and work such has the “practicum in loon and lake

ecology and management research project will be a major benefit to the loons and lakes

of Iron County.

Students responded positively to the project and many volunteered their time during the

summer break. They became proficient at selected chemistry testing, loon identification

and behavior and gained experience in canoeing and water safety. They were exposed to

issues relating to shoreline development, erosion control, invasive species, and buffer

preservation and we feel that they have a great insight on the overall story of loons and

lakes in Iron County.

Thank you for your support