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.

Scaup

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The term “scaup” refers to both the greater and lesser scaup, and they are very similar in appearance. Greater scaup are about one fifth larger than lesser scaup, and their heads are more round with an iridescent green sheen as opposed to purple of the lesser. A black nail on the tip of the bill is more prominent in greater scaup. Greater scaup breed in the far north on tundra wetlands, while lesser scaup range all the way from western Alaska to Ontario and south to the Dakotas. Of the two, lesser scaup are far more common, and probably make up more than 99% of the scaup counted at Goose Pond.

Greater scaup, photo by Paul Sullivan, FCC

Greater scaup, photo by Paul Sullivan, FCC

Lesser scaup, photo by    Mike Bons

Lesser scaup, photo by Mike Bons

During migration, scaup can gather into massive groups, and they are iconic birds to those who maintain an intimate relationship with large water bodies. In Wisconsin, this means the Mississippi River, Lake Superior, Lake Michigan, Lake Poygan, and Lake Mendota. There is a long and unique history of hunting scaup (or “bluebills” to waterfowlers) on Lake Winnebago. That is not to say, however, that they don’t use smaller habitats scattered through every county in the state. Twenty-five people from Wisconsin Society for Ornithology visited Goose Pond on a field trip to view the migration on March 23. Tom Schultz helped lead the field trip, and he reported seven lesser scaup and a single greater scaup.

Scaup are “diving ducks” which feed in over a foot of water and consume more animal matter, as opposed to ‘“puddle ducks” that skim the water or “tip” feeding mostly on vegetation. Even though row crop fields are terrible habitat for usual diving duck prey species like snails and mussels, scaup can take advantage of waste corn. Scaup banding efforts even bait their swim in traps with corn. The highest scaup concentrations at Goose Pond Sanctuary occur on flooded agricultural fields.

Lesser scaup pair, photo by Richard Armstrong

Lesser scaup pair, photo by Richard Armstrong

North American scaup populations have dropped by almost 50% from 8 million birds in 1975 to 4 million 2017 according to the US Fish and Wildlife Service estimates, and the downward trend is continues. Ongoing research spans habitat selection, migratory food preferences, and migration chronology among other important life history events. Hopefully it will reveal the best strategies for conserving this once abundant species.Although there is not a definitive cause, here are a few proposed theories for scaup decline:

Greater scaup hen, photo by Andrew Reding, FCC

Greater scaup hen, photo by Andrew Reding, FCC

Low Hen Survival- The survival of adult breeding hens has been shown to significantly influence population change. This is a well established perspective that spans the waterfowl community. We know it’s important, but data on the major drivers for hen survival is limited. Predation at nesting sites takes a heavy toll on hens, and unlike more reproductively competitive duck species, scaup don’t breed until their second year. This factor is readily visible at Goose Pond; only about 20% of the scaup surveyed were hens.

Contamination- Biomagnification causes higher heavy metal concentrations to build up in predators that feed in contaminated areas. Selenium can result in duckling deformities and poor health. To complicate this issue, recent studies show that scaup have been increasing their dependence on invasive zebra mussels as a food source, which contain more selenium than most of their native counterparts. Selenium enters the environment through mining, industrial manufacturing, and other human influence.

Wetland Loss- Much of the water in Canada and Alaska lies over a solid layer of permafrost. As permafrost melts, surface water is allowed to infiltrate into the ground and the land dries out. Canada is warming at twice the rate of the global average, and wetland loss related to melting permafrost will likely be a major contributor to the decline of scaup and an unknown number of species across biotic groups.

A graph showing the fluctuating presence of scaup, ringnecks, and canvasbacks at Goose Pond Sanctuary.

A graph showing the fluctuating presence of scaup, ringnecks, and canvasbacks at Goose Pond Sanctuary.

On March 29, I counted 620 scaup around Goose Pond, a record high count since MAS staff started regular waterfowl surveys started here in 1980. To be fair, the all time high count of 800 scaup was reported by William Hilsenhoff on April 9, 1960. They can presently be seen from Goose Pond Road or Kampen Road at ten yards or less associating with canvasbacks, redheads, and ring-necked ducks. Runoff from snowmelt caused Goose Pond water levels to rise to unprecedented levels, and waterfowl of all kinds are utilizing the flooded landscape for food and rest. Scaup populations are in rough shape, but seeing hundreds of them wheel around Goose Pond sparks optimism for the future of this striking species.

Written by Graham Steinhauer, Goose Pond Sanctuary land steward

Cover photo, lesser scaup by Mike Bons

Tundra Swan

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I first knew swans to be nasty things. A mute swan on a neighborhood pond would lunge at me when I got too near, and the popular depiction of swans as graceful elegant birds for me morphed into a fear of their hissing aggressiveness.

Tundra swans, meanwhile, are beautiful Holarctic migrants, moving through Wisconsin each spring and fall in large flocks, often associating with diving ducks like canvasbacks and redheads. These diving ducks will access tubers and grain in the bottoms of ponds and flooded ponds, while the swans can do the same with their long necks.

Tundra swans can be identified by their all white feathers, their black bill, and  a yellow spot on the lores. The birds will typically form pair bonds for life, and can live to be over 20 years old.

Unlike the non-native and stocked mute swan, which often sits solitary on a residential pond, the tundra swans congregate in great flocks of thousands of birds. In spring, these birds are moving from their wintering grounds on the Chesapeake Bay to breeding habitat on the Arctic Circle. 

Photos by Drew Harry

In the past week, a flooded field north of Faville Grove Sanctuary has been occupied by over 1,000 tundra swans and thousands of waterfowl including northern pintails, canvasbacks, redheads, scaup, mallards, northern shovelers, and ring-necked ducks. These huge migratory flocks tend to be uncommon at Faville Grove, since there are not any huge open water wetlands within the sanctuary. However, a wet start to spring has provided excellent habitat for migrating waterfowl in these flooded fields.

It’s not hard to appreciate the huge flocks of birds, especially the large and alluring tundra swans, as they make their way on an 1,800 mile journey to the north.

Written by Drew Harry, Faville Grove Sanctuary land steward

Cover photo by Monica Hall

Common Goldeneye

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As Wisconsinites, many of us pride ourselves on our cold tolerance during harsh mid continental winters. People joke about grilling shirtless in the snow, and we openly chuckle when southerners look like they’re about to cross open tundra at 55°F. Our confidence ends when open water is involved. Strong rivers like the Mississippi, Wisconsin, Wolf, and Rock have high enough flow rates to keep from freezing, and the Great Lakes also retain open water. Because it is a poor insulator, water saps heat from the body with deadly speed. Common goldeneyes (Bucephala clangula) and a few other hardy water birds in Wisconsin don’t huddle on the surface in a melancholy group, but rather splash around as though enjoying a warm bath.

Drake common goldeneye. Photo by Jim Edlhuber

Drake common goldeneye. Photo by Jim Edlhuber

Drakes are black and white with an iridescent black and green head that features a conspicuous round white spot near the base of their bill. Hens have a brown head, yellow bill tip, and gray body. Goldeneyes do indeed have golden eyes, but this is not diagnostic as many other diving duck species claim this characteristic. Strong wedge shaped bills are perfect for crushing shellfish and other aquatic invertebrates. Fish and fish eggs are also preferred food sources, and goldeneyes usually forage in water that is five to twenty feet deep.

Common goldeneyes trend as far north during winters as the ice line will allow. They are some of the last ducks to show up during the fall migration and are early pioneers in the spring. The first ducks to arrive at Goose Pond this year were a trio of goldeneyes, and they’ll likely be headed north to Canada’s boreal forest for breeding within the next week. Low densities of goldeneyes do nest in Wisconsin with concentrations around the boreal forest habitats of Bailey’s Harbor, Door County and Lake Namekagon. It is well known that wood ducks are cavity nesters, but three species of diving ducks utilize tree cavities including buffleheads, hooded mergansers, and goldeneyes.

Characteristic trees of a boreal forest are conifers like spruce, balsam fir, and tamaracks, but some deciduous species like aspen, cottonwood, and white birch are mixed in. Conifers make for poor cavity trees as their wood is less susceptible to microbial decay, and the deciduous species listed above are prone to rapid deterioration and toppling over at a young age. Goldeneyes can’t dig into trees, so how do sufficient amounts of nesting cavities exist in boreal forests?

Pileated woodpeckers and northern flickers are primary excavators, meaning that they mine new holes into trees with their specialized beaks. The cavities are used in subsequent years by  wildlife (secondary cavity nesters) including flying squirrels, chickadees, nuthatches, barn owls, buffleheads, goldeneyes, and a plethora of other bird species. Goldeneyes have been found nesting in wood duck boxes, but this is rare because duck boxes are not usually erected within the goldeneye breeding range.

Common goldeneyes and buffleheads. Photo by Arlene Koziol

Common goldeneyes and buffleheads. Photo by Arlene Koziol

With an abundance of sheetwater at Goose Pond, waterfowl species are gravitating to the area in search of food, rest, and potential breeding sites. Goldeneyes, redheads, scaup, buffleheads, ring-necked ducks, hooded mergansers, pintail, widgeon, mallards, wood ducks, and Canada geese can all be viewed from Kampen Road. Check out the Goose Pond eBird Hotspot to see what birds are on the pond, and to record what you see.

Muskrat family in the sun. Photo by Richard Armstrong

Muskrat family in the sun. Photo by Richard Armstrong

Record high water levels flooded muskrats out of their houses, and now groups of eight or ten individuals commonly squish themselves together to sunbathe in a furry clump within fifty yards of Goose Pond Road. Almost all goldeneyes will be gone by April, so don’t hesitate to come out and look for them. Goldeneyes still have to travel hundreds of miles north to arrive at their core breeding grounds, and they certainly won’t wait for you.

Written by Graham Steinhauer, Goose Pond Sanctuary land steward

Red-winged Blackbird

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King of the cattail, the wicked black bird with his yellow epaulets flares his wings, exposing scarlet shoulders and a penchant for conflict. We are encountering, of course, the red-winged blackbird, one of the most abundant birds on the continent of North America.

Their territoriality sticks with many people, be it on bike paths, wetland walks, or a hike near some cattails. Male red-winged blackbirds spend more than a quarter of daylight hours defending territory. A number of hypotheses might explain the fierce defense of red-winged blackbirds. First, the parental investment theory holds that as the age of the nest increases so will the territoriality of the parents. Research suggests this is a strong tendency for red-winged blackbirds, and this theory further predicts that territoriality will increase with an increased clutch or brood size, which is indeed the case for these blackbirds.

Photo by Monica Hall

Photo by Monica Hall

Interestingly, a Journal Sentinel article was published last year on June 29, 2018 detailing red-winged blackbird “attacks” on pedestrians along the lakeshore. These were likely birds with defending nestlings about to fledge; according to the first Breeding Bird Atlas, the median fledgling date was July 1. These blackbird attacks were desperate attempts to protect their investment in young, and the fiercest attackers might have had more young to protect.

Second, the renesting potential hypothesis predicts that nests later in the season will be defended more fiercely due to slim odds of successfully reproducing again so late in the season. Again, this appears to hold true for male red-winged blackbirds.

An unamused sandhill crane getting mobbed by a red-winged blackbird. Photo by Arlene Koziol

An unamused sandhill crane getting mobbed by a red-winged blackbird. Photo by Arlene Koziol

A red-winged blackbird mobs a swan family to protect a nearby nest. Photo by Alrene Koziol

A red-winged blackbird mobs a swan family to protect a nearby nest. Photo by Alrene Koziol

A story, from Antigo on August 11, 2017 shows pictures of a red-winged blackbird attacking and even landing on a bald eagle. According to the photographer, there was a nest nearby. Here, again, we see an extreme example of aggressiveness in this bird, and it can be explained by the renesting potential hypothesis, since the odds of the bird renesting and successfully raising a clutch after August 11 were near zero. The latest date for fledged young according to data from the first Breeding Bird Atlas was August 19, so if the chicks in this nest had not yet fledged, they were likely a second or third nesting attempt.

In summary, early on in the season, early to mid-June, the aggressive birds are likely protecting a nest, and that nest probably is farther along and holding more eggs based on the aggressiveness of the bird. Later in the season, red-winged blackbirds will fiercely defend a renesting attempt, as it’s the last chance for the bird to reproduce that season.

While extremely common and abundant, red-winged blackbirds have undergone a 30% population decline since 1966. This might be attributed to a number of factors, including continent-wide wetland losses and degradation. While we’re not at risk of losing red-winged blackbirds any time soon, their overall decline suggests a worsening of habitat, especially for wetland birds.

Red-winged blackbird nest parasitized by a brown-headed cowbird in an upland setting. Photo by Drew Harry

Red-winged blackbird nest parasitized by a brown-headed cowbird in an upland setting. Photo by Drew Harry

Another reason to protect these wetland habitats is that red-winged blackbirds have reproductive success in wetlands and marshes. According to the Breeding Bird Survey, only 2% of nests in marshes were parasitized by brown-headed cowbirds, whereas 17% were parasitized in upland settings. Nest success was 48% in wetlands but only 33% in uplands.

At Faville Grove you can find boisterous red-winged blackbirds throughout the sanctuary. They’ve just returned to the area in the past week.

 Written by Drew Harry, Faville Grove Sanctuary land steward

Cover photo: Kelly Colgan Azar