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
sta
l
Deer
Fo
x
Gra
nd
Po
rtag
e
Pard
ee
Gil
e
Flo
wa
ge
Lit
tle
Pik
e
Pin
e
Hew
itt
# o
f C
hic
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
sta
l
Deer
Fox
Gra
nd
Porta
ge
Pard
ee
Gile
Flo
wag
e
Little
Pik
e
Pin
e
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
2
4
6
8
10
12
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visi
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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
2
4
6
8
10
12
14
16
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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