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Common Loon

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One of the most iconic species of summer in the northern forest, the common loon beckons admiration, from wooden carvings, gift shop trinkets, ring tones, and paintings. For those spending a vacation around a campfire in northern Wisconsin, loons lay the soundtrack in equal parts to the campfire.

In fact, I think the distribution of common loon breeding in northern Wisconsin is a good approximation for the southern limits of “up north.”

Rough approximation of “up north” based on common loon breeding range in Wisconsin. Image courtesy of eBird

Rough approximation of “up north” based on common loon breeding range in Wisconsin. Image courtesy of eBird

The Journal Sentinel has developed a map where you can draw your own line for where “up north” is located; most agree, it follows a line a little north of Green Bay west to about Chippewa Falls.

Over the course of the year, loons will move through southern Wisconsin, typically occupying larger bodies of water along the way. Lake Mendota in Madison and Rock Lake in Lake Mills are two excellent spots to view the common loon right now as it migrates through the area.

Colorful common loon on Lake Monona, April 4, 2019. Photo by Pat Ready

Colorful common loon on Lake Monona, April 4, 2019. Photo by Pat Ready

Lake Monona loon, april 4, 2019. Photo by Pat Ready

Lake Monona loon, april 4, 2019. Photo by Pat Ready

During migration, loons with tracking devices have been recorded on dives of 174 feet.  If you see any loons on Lake Mendota this spring, imagine the deep hole between Picnic Point and Maple Bluff. That’s 82 feet deep, so loons can dive to depths of more than two Lake Mendota’s!

Listen to the calls of the common loon, and watch how it deftly dives and swims underwater. Video by BR Valley.

Historical accounts indicate that loons did nest in parts of southern Wisconsin. A number of factors conspired to limit the loon’s range to the northern expanse of Wisconsin, including wetland loss and degradation, mercury bioaccumulation, and lead poisoning.

Loons nest within a few feet of the water, and wetlands at the edge of lakes are critical to nesting success. A common spot for loon nests is on the floating sphagnum mat at the edge of relatively acidic lakes in northern Wisconsin. Unfortunately for loons, lakefront development can negatively impact the ability to nest.

Good habitat on a sphagnum mat, inset: no habitat. Photo courtesy of Mike Meyer, “Twenty Four Years of Common Loon Research in Wisconsin”

Good habitat on a sphagnum mat, inset: no habitat. Photo courtesy of Mike Meyer, “Twenty Four Years of Common Loon Research in Wisconsin”

Researchers have found that development of housing greater than 25 buildings per kilometer of shoreline prevents loons from nesting in the area. Housing development usually leads to the degradation or elimination of wetland habitat along shorelines.  It doesn’t need to be this way. Many alternatives to a barren lawn exist that beautify the yard and add habitat for wildlife, and protect the erosion into the lake.  You can find numerous excellent examples here.

The map below is from the USDA Forest Service’s North Central Research Station and shows how housing density has increased in northern Wisconsin since 1940.

Image from  Wisconsin’s Land Legacy Report

Image from Wisconsin’s Land Legacy Report

Having the pleasure of loons on your lake can come with a number of responsibilities. Known nesting sites should not be disturbed during the summer. If there are known nesting sites, efforts should be made to reduce wake in those areas. Additionally, lead fishing tackle contributes to significant mortality each season. In Minnesota, one study found that 15-20% of dead loons had lead poisoning. Using non-lead alternatives is good for loons and the whole ecosystem. One of the biggest items on Wisconsin’s Conservation Congress hearings this past week was a ban on lead tackle and ammunition. This would have positive impacts for the loon population, and it is estimated that a lead ban would save over 50 loons in Wisconsin each year.

An issue outside of a loon enthusiast’s direct control is the emission of mercury from coal-generated power plants. As stated before, loons are sensitive to the bioaccumulation of methyl mercury because they are high in the food chain, long lived, fish-eaters, and nest on acidic lakes, which tend to have higher availability of mercury to move up the food chain (pictured below).

As pH decreases (becomes more acidic) mercury concentrations increase in both adults and chicks of common loons. Graph courtesy of Mike Meyer, “Twenty Four Years of Common Loon Research in Wisconsin”

As pH decreases (becomes more acidic) mercury concentrations increase in both adults and chicks of common loons. Graph courtesy of Mike Meyer, “Twenty Four Years of Common Loon Research in Wisconsin”

A new EPA proposal would roll back some limits on emissions of mercury for coal-burning power plants. This could have a huge effect on public health, and different accounting estimates calculate the potential indirect benefit of saving thousands of lives due to the “co-benefit” of also decreasing particulate matter linked to lung and heart disease. In Wisconsin, coal-burning power plants have been granted exceptions for mercury emissions. Beyond public health, mercury for loons spells trouble. 

As mercury increases, hatching rates decrease beyond a sustainable number. With high mercury concentrations in the food chain, adults become lethargic and might not reproduce at all. This decreases the likelihood of success for the common loon, which already faces difficult enough odds on its breeding grounds where approximately 50% of nests fail, due to predation, flooding, or other causes.

Another twist might occur as the climate continues to change. With flooding more likely, the amount of mercury in aquatic systems may also increase. Research from UW-Madison’s Center for Limnology has found an interesting correlation between annual water levels and the concentration of mercury in walleye. You can see that interesting blog post here. With flooding and high water levels, loons may be even more susceptible to mercury bioaccumulation.

While fragile, the outlook for loons in Wisconsin is rather positive. Since 1980, the population has nearly doubled and continues to increase. If you’re able to help, you can sign up for Northland College’s Loonwatch, which aids research in a number of areas.

Written by Drew Harry, Faville Grove Sanctuary land steward

Cover photo by Arlene Koziol

Sources

Stewart, S. I., Hammer, R.B., Radeloff, V.C., Dwyer, J.F., & Voss P.R. 2003. Mapping Housing Density across the North Central U.S., 1940-2000 [Slide show]. Available: http://www.ncrs.fs.fed.us/IntegratedPrograms/lc/pop/hd/title.htm

Meyer, Mike. "Twenty Four Years of Common Loon Research in Wisconsin." Microsoft PowerPoint file. Accessed here.

Puerto Rico: Winter Habitat for Birds and Humans

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According to the Wisconsin Society for Ornithology, 439 bird species have been observed in our state. It’s true that some of those are considered rare or accidental migrants, but the number still stands. When temperatures drop below freezing, virtually all above ground insects are killed, wildlife cover is reduced as plants senesce, and liquid fresh water becomes scarce. The 439 bird species drops to 111.

During the first two weeks of January, Calla Norris (UW-Madison student and bird enthusiast)  and I traveled to Puerto Rico. This United States territory is known for its high biodiversity despite small relative size. For reference, Puerto Rico is about 6% of Wisconsin’s land area but harbors a similar number of bird species (363). Our goals were to snorkel the coral reefs, experience a different culture, and observe new plant and animal species.

- Corals, octopi, jellyfish, eels, dinoflagellates (bioluminescent diatoms), lobsters, rays, crabs, urchins, flying fish

- Ate traditional suckling pig, visited shade-grown coffee farms, ate several coconuts which we opened ourselves, petted many stray dogs

- belted kingfisher, red-tailed hawk, blue-winged teal, common yellowthroat, mourning dove, house sparrow, killdeer, spotted sandpiper.

Mourning dove by USFWS National Digital Library

Mourning dove by USFWS National Digital Library

Blue-winged teal? Mourning dove?! We could have traveled to virtually any county in Wisconsin during the growing season to encounter them. My point here is not to devalue these species by calling attention to their commonness or wide distribution, but to reaffirm the value of borderless bird conservation. Providing habitat for migratory birds in Wisconsin is essential, however, it’s easy to forget that wintering grounds and stopover sites are also of critical importance.

The concept of borderless bird conservation was formally established in 1918 with the passing of the Migratory Bird Treaty Act. Ornithologists, notably waterfowl enthusiasts, realized that conserving habitat over vast spatial scales is crucial to maintaining population levels of migratory species. A prime example of this is the indigo bunting. This striking songbird of edges and shrubby fields nests in high densities throughout the eastern United States. During the winter, indigo buntings travel to Central America and Caribbean islands. Only a tiny portion of the population remains within the political boundaries of the United States. Even if huge tracts of prime breeding habitat are provided in the US, indigo buntings would surely decline or disappear if their wintering areas in other countries were decimated.

Indigo bunting by USFWS National Digital Library

Indigo bunting by USFWS National Digital Library

Indigo bunting range map by Cornell Lab of Ornithology

Indigo bunting range map by Cornell Lab of Ornithology

Calla and I explored as many new ecosystems as possible. They ranged from dry forests dominated by cacti in the Guanica State Forest and Biosphere Reserve to the rainforests of El Yunque which receive about 240 inches of rain annually. On Vieques, a small island off the east coast of Puerto Rico, Calla approached a group of fifteen people wielding machetes and hand saws to inquire about their curious (if not threatening) accessories. They were volunteer trail builders for the Vieques Conservation and Historical Trust, and we offered to join them. After chopping and chatting with students and trust members alike, we learned some birding hotspots. At all locations we observed birds that can be put into three categories: 1) species native to Wisconsin (or other northern regions), 2) pelagic generalists, and 3) species that are endemic to the Caribbean or Puerto Rico itself. Okay, so we’ve established that providing habitat at warmer latitudes is required to maintain migratory bird populations in addition to the non-migratory locals. Now let’s check that box:

- Yellow-crowned night heron, brown booby, black-necked stilt, white-cheeked pintail, gray kingbird, brown pelican, royal tern, smooth-billed Ani, American oystercatcher, Puerto Rican tody, greater Antillean grackle, and 30 or so others.

Puerto Rican Tody by Annabelle Watts

Puerto Rican Tody by Annabelle Watts

Yellow-crowned night heron by USFWS National Digital Library

Yellow-crowned night heron by USFWS National Digital Library

Next time you take a trip south, keep an eye out for the rarities, the unexpected, the lifers. But watch out too for birds native to your own state. Sure you might regularly see them out your back door, but old birds in new places remind us of their complex life histories, ignorance of political boundaries, and need for wide-ranging if not global conservation efforts.

 Written by Graham Steinhauer, Goose Pond Sanctuary land steward 

Lapland Longspur

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The Lapland Longspur, a winter bird here in Wisconsin, perhaps best represents the arctic chill currently swallowing the Midwest. The longspur breeds on the highest of the high arctic, residing on the tundra grasslands that typically reserve this -30 degree Fahrenheit air.  On its breeding territory, the longspurs display a brilliant black bib, face, and crown, a rusty nape, and a vibrant yellow beak.

Lapland longspur in its summer breeding grounds. Photo by Fiona Paton FFF

Lapland longspur in its summer breeding grounds. Photo by Fiona Paton FFF

This species eats seed during its winter foray into Wisconsin, a diet which its bill is well-adapted for. Here at Faville Grove Sanctuary, I wonder if these birds are finding sufficient food for the winter, but the staggering diversity and weight of seed in a prairie restoration should easily last the winter. I’ve seen longspurs along the edges of fields down Prairie Lane this winter.

Because of its high arctic breeding grounds, very little is known about the Lapland longspur in terms of population or ecology. The overall population seems to be healthy, as this is a common winter bird of the northern United States.

Lapland longspur photo by Nigel, FCC

Lapland longspur photo by Nigel, FCC

One study on longspurs found that the birds show a slight spike in testosterone during the breeding cycle when they use song displays and participate in courtship. This spike lasts for two days. Over the next week or so, the males will vigorously defend the female they are paired with. Outside of this week-long window, male longspurs are quite affable and tolerant of other males entering their territory. Other species, in studies involving testosterone, have shown longer-lasting spikes of testosterone and exhibit agressive behavior for a much longer time period, even over a month long. The chill of the Lapland longspurs goes beyond their general habitat and infiltrates their very demeanor.

You might find Lapland longspurs down Prairie Lane, once the snow has melted a bit.

Written by Drew Harry, Faville Grove Sanctuary land steward

Snowy Owls Galore

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Snowy Owls: Goose Pond, Arlington, and Coddington

Madison Audubon’s involvement with Project SNOWstorm began in February 2015 when Goose Pond Sanctuary experienced many observations of snowy owls as winter visitors. Project SNOWstorm was just getting started as a non-profit that studies snowy owls’ winter ecology after the historic snowy owl irruption of 2013-14.

What had once been simple (excited) observations of snowy owls near Goose Pond led to a parntership with Project SNOWstorm and local biologists to safely capture, place a transmitter on the back of, and release these birds back to the wild. We hope that those involved with “our” two snowy owls at Goose Pond — Goose Pond and Arlington — enjoy the memories of those events, and that new birders can learn about the snowy owl project. And now, we have the pleasure of watching a third owl associated with our organization: Coddington.

The three snowy owls Madison Audubon and its donors have supported as part of Project SNOWstorm. Left: Goose Pond (2015), photo by Richard Armstrong. Center: Arlington (2018), photo by Madison Audubon Society. Right: Coddington (2019), photo by Brad Zinda.

Over the past four decades snowy owls are seen infrequently at Goose Pond but sightings increased in the winter of 2013-2014 in our area. Ryan Brady, DNR Conservation Biologist provides updates on snowy owls, and this winter, 85 have been sighted in Wisconsin, but so far not on our sanctuary.   

Over 75 snowy owls have been tracked by Project SNOWstorm throughout the United States and Canada, including three owls with transmitters funded by MAS donors. The first bird, “Goose Pond”, was caught and released on February 14, 2015; “Arlington” on January 4, 2018; and “Coddington” and on January 3, 2019.


Mark Martin releasing the newly tagged Goose Pond owl. Photo by Arlene Koziol

Mark Martin releasing the newly tagged Goose Pond owl. Photo by Arlene Koziol

“Goose Pond” (2015)

Our first snowy owl was caught at the Central Wisconsin Airport at Mosinee, released at the UW Arlington Research Station one mile south of Goose Pond, and named after our nearby iconic wildlife sanctuary. (Conservation groups actively work on relocating owls that are found at or near airports due to the high risk for the birds and planes.) On March 19, Goose Pond flew southwest to Grant County, and his last transmitted data was six miles northwest of Dubuque, Iowa on March 29. Shortly after that his transmitter failed. We later learned that he spent time near Highway 151 near Platteville. When learning that he moved to a rural area in Grant County, Mark Martin, Matt Reetz, and raptor biologists from Eagle Valley tried trapping him so that his failed transmitter could be removed, but were unsuccessful.


Arlington’s piercing gaze is unforgettable. Photo by David Rihn.

Arlington’s piercing gaze is unforgettable. Photo by David Rihn.

 “Arlington” (2018)

Of all the transmitted owls in the Midwest, Arlington made the most movements away from and back to his release sight at the UW Farms. Project SNOWstorm scientist Scott Weidensaul wrote in the February 18, 2018 Project Snowstorm blog that “Arlington took a little walkabout Feb. 12-13, making a 90-mile (144 km) jaunt east to the outskirts of Watertown, south to Lake Koshkonong, and then back up to his normal (Arlington) territory.” Arlington later took a cruise to Rush Lake near Ripon and returned. That April, the Midwest was hit with giant spring snowstorms, delaying the bird’s migration back to the tundra.

A map of Arlington’s extensive travels while in Wisconsin. Image provided by Project SNOWstorm.

A map of Arlington’s extensive travels while in Wisconsin. Image provided by Project SNOWstorm.

From Project SNOWstorm’s May 13, 2018 blog: “…there’s been a lot going on, so let’s bring everyone up to speed. Unfortunately, the biggest news is also the saddest. Arlington, who was tagged Jan. 4 at Madison Audubon’s Goose Pond Preserve near Arlington, Wisconsin, was found dead along a roadside in Benton County, Minnesota, on April 29. Although we’ll conduct a necropsy to be sure, it appears he was killed by a vehicle collision — our third such loss this winter. A passerby saw a snowy owl sitting along a country road, not moving, and when they returned half an hour later, the owl — Arlington — was lying dead.

We’re deeply grateful to Carroll Henderson and the other folks at Minnesota DNR, who recovered Arlington, for reaching out to us immediately and making arrangements to have him and his transmitter shipped to us — just another example of the terrific cooperation we’ve enjoyed over the years from state, provincial and national wildlife agencies.  And we’d like to again extend our thanks to Madison Audubon for sponsoring Arlington’s transmitter — this is a hard loss for them as well as us, but Arlington’s movement data is and will remain a valuable legacy.”

Project SNOWstorm sent us the results of his necropsy that found low (sublethal) levels of Brodifacoum rodenticide, and also DDE, the breakdown product of DDT, which we find at varying levels in many snowy owls, and significant levels of mercury. We’re looking hard at what such toxins mean for snowy owl health. He had a moderately heavy load of parasitic nematodes, which we’ve seen at fatally high levels in some snowy owls.

Fortunately, Project SNOWstorm was able to recover Arlington’s transmitter and refurbish it for another bird in the future. While Arlington’s death was a blow, the prospects of tagging another owl with the transmitter gives Arlington’s followers and the donors to the $3,000 transmitter a second chance to hope.


Coddington, the snowy owl outfitted with Arlington’s transmitter, in profile. Photo by Brad ZInda.

Coddington, the snowy owl outfitted with Arlington’s transmitter, in profile. Photo by Brad ZInda.

“Coddington” (2019)

And a second chance came this winter! Coddington, an adult male snowy owl, was caught and released at Buena Vista Marsh on January 3, 2019 and outfitted with “Arlington’s” transmitter. The perils of winter life for snowy owls continue, however, as we learned this week that he made a narrow escape from disaster with help from a farm family in Plover and the Raptor Education Group, Inc. (REGI). Likely after chasing prey into a barn and getting stuck inside, and in a lagoon of cow manure no less, Coddington was rescued by the Biadasz family, cleaned up, examined, and is currently in rehab with REGI.

Because Coddington will be in rehab and stationary for three to four weeks, his transmitter was removed and we’re hoping to be able to capture, tag, and release another snowy owl with that transmitter. We are so glad Coddington will recover and in time to migrate north!


Arlington sits at the rock quarry outside of Goose Pond Sanctuary in 2018. Photo by Monica Hall

Arlington sits at the rock quarry outside of Goose Pond Sanctuary in 2018. Photo by Monica Hall

As you can see, snowy owls — indeed, most bird species — face numerous challenges when interacting with the human world. But programs like Project SNOWstorm, which work to understand those specific challenges, people like you and I, who work hard to take action to help birds like Goose Pond, Arlinton, and Coddington, can make a world of difference.

Thank you to:

  • Project SNOWstorm for establishing and coordinating the snowy owl winter ecology research project. Their staff of volunteers is great to work with!

  • Gene Jacobs, Raptor Biologist with Linwood Springs Research Station for catching and banding the three owls.  

  • MAS members that donated to funding two transmitters and to donors to Project SNOWstorm.

  • Everyone who provided sightings and photos, and helped trap the owls.

  • The staff at UW Arlington Research Farms for their reports and cooperation.

Together, we can make a difference!

Written by Mark Martin and Susan Foote-Martin, Goose Pond Sanctuary resident managers, and Brenna Marsicek Madison Audubon director of communications

Forster's Tern

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Female Forester’s tern. Photo by Arlene Koziol

Female Forester’s tern. Photo by Arlene Koziol

Terns are in the same family as gulls and skimmers, and 40 tern species are found worldwide. The arctic tern migrates from Antarctica and back again over a six month period. Their journey is not necessarily in a straight line, and on average the round trip migration distance covers an unbelievable 44,000 miles. All four tern species regularly found in Wisconsin, Forster’s tern, black tern, common tern, and Caspian tern are listed as state endangered. Wisconsin DNR and other groups have developed innovative ways to assist these species, and particular progress has been made with Forster’s terns.

Numerous Forster’s terns mingle in native vegetation in a wetland. Photo by Daryl Christensen

Numerous Forster’s terns mingle in native vegetation in a wetland. Photo by Daryl Christensen

The Forster’s tern is a colony nester. Bird colonies are usually found on sites that are well protected from the usual terrestrial predators. Because colony nesting birds only congregate for a small portion of the season, local predator populations do not boom as they might with a permanent high energy food source. Forster’s terns breed in large marshes with abundant emergent vegetation, and most of the breeding population in Wisconsin inhabits the east central portion of the state or lower Green Bay.

In pre-settlement days, an estimated 10 million acres of wetlands existed in Wisconsin according to Wisconsin DNR. Around 50 percent of those acres were destroyed because of conversion to agriculture, urban area, or other uses. Some colony nesters have a remarkably high site fidelity, meaning that they return to the same breeding site year after year. Forster’s terns are more nomadic than others in this sense. They require specific water levels for optimal nest success; plenty of water to maintain prey populations and deter predators, but not so much that their source of cover is below the water line. Historically Forster’s terns had many more options when choosing a colony site. Greater habitat choice led to more successful nests and higher populations.

A Forster’s tern on a nest platform, Photo taken by Daryl Christensen in 1983 or 1984

A Forster’s tern on a nest platform, Photo taken by Daryl Christensen in 1983 or 1984

Because of low nest success and declining populations, the Wisconsin DNR began deploying nesting platforms for Forster’s terns in 1983. Nest platforms provide high quality nesting sites when natural substrates are of low quality or in short supply. After eggs are laid, rising water can easily submerge nests. Fluctuation in marsh water levels is likely exacerbated by hard surfaces and row crop cultivation due to their low water infiltration potential. Nesting platforms float on the water surface. They are attached loosely to a pole which allows them to rise and fall in response to changing water levels.

Nesting platforms significantly increase nest success, and 100 percent of deployed platforms were utilized by terns in 2018. This year at Lake Puckaway, 200 breeding pairs produced 259 eggs without the assistance of platforms. At Grand River Marsh, 19 breeding pairs that were occupying tern platforms produced 58 eggs. This means that breeding pairs of Forster’s terns were able to produce over two times the eggs using platforms than on natural substrate. Lake Puckaway flooded after this nest survey was completed, and all eggs were lost. Forster’s terns do renest, but their egg production decreases after each nesting attempt.

The Wisconsin DNR plans to increase the number of tern platforms to 150. Ryan Zabs, a Sun Prairie Eagle Scout, reached out to Goose Pond Sanctuary in search of his final Eagle Scout project. He helped us take a huge step towards those 150 by building 50 platforms in a single weekend. Sumner Matteson with Natural Heritage Conservation Bureau at WIDNR generously provided funding for the platform materials.

Forster’s tern nest platform, photo by Daryl Christensen

Forster’s tern nest platform, photo by Daryl Christensen

While the success of tern platforms certainly is exciting, it must be noted that this is not a permanent solution. Continued restoration of large wetlands and further protection of coastal wintering grounds is the best hope to keep Forster’s terns on the Wisconsin landscape now and far into the future.

Written by Graham Steinhauer, Goose Pond Sanctuary land steward