Foster's Tern

This summer, a great blue heron spent what seemed like its every waking (and sleeping) moment on a wood duck box on the Hwy 89 pond. Every walk around the pond yielded a surprise when a tall figure against the backdrop of prairie, pothole, and aspen turned out to be the heron, again perched on the wood duck box.

There was one instance where this heron departed from its usual routine, as far as we saw it. While the interns and I were on North Shore Road, we witnessed the heron land in the pond. We observed the bird with binoculars for a minute, before it quickly stabbed a bullhead out of the water, gulped it down after a couple of tries, and then returned—where else—to the wood duck box.

In his regular perch. Photo by Drew Harry

I was surprised by the size of the fish in the pond. Yet years past have seen egrets, pelicans, and great blue herons raiding this resource.

I was also surprised, on July 19, when I witnessed a Forster’s tern flying over the 89 pond. This is an endangered bird in Wisconsin that nests in colonies, so my sighting was unlikely to be breeding individual of the immediate area. However, my sighting occurred right around the time when young are fledging, and after this period, parents often disperse more widely to forage for minnows in lakes, rivers, and ponds.

Foster’s tern at Hwy 89 pond. Photo by Drew Harry

In the area of Faville Grove, one nearby location stands out as a potential breeding location for Forster’s terns. The Chub and Mud Lake Riverine Marsh to the north, in Dodge County, covers nearly 7,000 acres of wetland habitat and harbors the appropriate riverine marsh habitat often preferred by Forster’s terns. Portions of this area were never platted during the Public Land Survey, because they were presumed to be a lake. For Wisconsin’s second Breeding Bird Atlas, a number of probable breeding pairs were found in this area.

Faville Grove likely holds wetlands too small and isolated to host breeding Forster’s terns. These birds look for extensive wetland marshes, often nesting on well-concealed islands of vegetation to avoid mammalian predators. Raccoons, skunks, opossums, and weasels, could all decimate the eggs of a colony of Forester’s terns, so nest site selection is key for these birds.

For this reason, only a few colonies in Wisconsin traditionally produce offspring. These areas include Big Muskego Lake, the upriver lakes of the Winnebago Pool, Rush Lake, and the western shore of Green Bay.

It’s interesting to note that many wetlands in the immediate vicinity of Faville Grove contain islands of potential habitat for Forster’s terns. Due perhaps to the unique chemical makeup of these low-lying areas, most boggy lowlands are surrounded by a “moat” of open water, which typically rings the entirety of the wetland.

Wetland “moat” at Faville marsh. Narrow areas of water are likely due to erosion. Native vegetation will replace agricultural field and hold the soil in place in the far upper left of this photo, credit Rob Couey

There are a number of explanations for this moat, including runoff from uplands that increases decomposition and fires running into the edge of the wetland and increasing decomposition. The result is an open island of wetland vegetation with portions dominated sedges and cattails—seemingly perfect habitat for Forster’s terns. Farm field erosion can complicate dynamics of this moat, however. Runoff and siltation from upland areas can fill in this moat, and allow predators to access the island, while also making it more likely that it dries down during summer and fall.

Overall, the Forster’s tern is a chance occurrence at Faville Grove, but we’re happy to support their post-breeding foraging efforts. These birds have migrated through southern Wisconsin at this point, and are likely somewhere in Central or South America. These birds will return in late April, looking for the perfect island of wetland vegetation.

Written by Drew Harry, Faville Grove Sanctuary land steward

Not-So-Spooky Bats

With Halloween just around the corner, let’s talk about a furry, flying critter with an unfairly ghoulish reputation: Bats.

Hoary bat, one of Wisconsin’s eight native bat species. Photo by Daniel Neal, Oregon State University FCC

Of the 5,416 mammal species on Earth, about 1,200 of them are bats. This makes bats the most diverse mammal group second only to rodents. We have eight native bats here in Wisconsin, and they are all insectivores that prefer to eat beetles, stinkbugs, leafhoppers, and moths. Many of these insects are agricultural pests, and through their pest reduction services, bats have a huge positive impact on farmers. Flies and mosquitoes that directly impact humans are also on the menu.

Bats have been heavily persecuted by humans because of common myths associated with them, a fear of their unknown habits, and their general appearance. Let’s dispel some of those harmful bits of misinformation, shall we?

1. Myth: Most bats have rabies. Fact: Less than one percent of bat individuals have rabies.

2. Myth: Bats like to land in your hair. Fact: Bats may fly around you at night, but that’s only because insects are attracted to the heat and carbon dioxide that humans give off. Their goal has nothing to do with your hair. 

3. Myth: Bats will suck your blood. Fact: Only three species of bats in the world feed on blood, and they all live in Central or South America.

4. Misconception: Bats are ugly. Counter argument: To each their own on this one, but I can say with confidence that not all bats are ugly. There’s a reason that some species of bats, like this cutie below, are called flying foxes.

Young flying fox. Photo by Australian Bat Clinic and Wildlife Trauma Centre

There are four major threats to bat populations including bioaccumulation of pesticides, hibernacula disturbance, wind turbines, and white-nose syndrome (WNS). WNS is by far the most pressing issue. 75-100% of all bats in a hibernaculum (usually a cave or mine) are expected to die if the colony becomes infected with WNS. WNS is caused by a fungus. How it causes such high rates of mortality is somewhat unknown, but it is generally accepted that WNS causes bats to awaken from their hibernation period costing them precious energy. 

Map by White-Nose Syndrome Response Team

Each species of bat emits their own distinct frequency while searching for food. Scientists developed bat survey equipment with this auditory footprint in mind. The machine “listens” for bats, determines what species was present, and adds the associated coordinates to create a bat survey map. Mark Martin, Sue Foote-Martin, and Brand Smith started conducting bat surveys at Goose Pond Sanctuary and Schoeneberg Marsh in 2008. Bats found on past surveys in our area have included big and little brown, hoary and eastern red bats.  A silver-haired bat found on the recent Schoeneberg Marsh count is new species to the bat list. 

This baseline data is valuable in determining what bat species are declining most heavily. On August 6, 2019, Tanner Pettit (summer Goose Pond intern) and I replicated a bat survey from 2016. Note that the time of year, time of night, water levels, and wind speeds are all similar between the two surveys. Each symbol on the map represents one bat encounter. The results were sobering.  

Results of the 2016 Bat Survey. Map by WDNR Bat Program

Results of the same survey done in 2019. Map by WDNR Bat Program

Andrew Badje, DNR Conservation Biologist, downloaded the 2019 bat data for Goose Pond and Schoeneberg Marsh and said, "On that note, 4 species/survey is a great result, for the WNS world we currently live in.” Bat counts have also been conducted at Goose Pond and have found similar results.

Little brown bats in a hibernaculum. Photo by Petroglyph FCC

Bats are sometimes grouped by habitat preference. Tree bats usually roost in small groups under bark or in tree cavities. As the name implies, cave bats usually roost in caves or mines. The largest known bat colony is called Bracken Cave in Mexico, and it hosts 20 million bats annually. This makes it the largest concentration of mammals ever discovered. Because cave bats pack themselves closely together for warmth and to conserve space, they are particularly susceptible to diseases like WNS.

Little brown bat with white-nose syndrome. Photo courtesy of USFWS National Digital Library.

As you can see from the bat survey map of Schoeneberg Marsh above, bats of all species have declined sharply except for big brown bats since 2016. While big browns are cave bats, their larger body size probably helps them survive the winter better than smaller bodied bats. Solutions for WNS like vaccines and hibernacula climate control are in the works, but our window to save bat populations is rapidly closing. 

Written by Graham Steinhauer, Goose Pond Sactuary land steward

Blue-headed Vireo

The world over, how many birds have blue heads? Most of those birds, one might imagine, are located in the tropics—nestled away in exotic rainforests. A quick “blue-headed” query into eBird reveals blue-headed wood-doves, coucals, hummingbirds, sapphires, bee-eaters, parrots, macaws, and racquet tails, among a legion of other blue-headed birds. Most of these birds are indeed tropical, ranging from West Africa to Colombia to Caribbean endemics.

One bird with a blue head can be found in Wisconsin, among nine or so others, breeding in the northern mixed conifer forests in summer, and migrating through southern Wisconsin in October and early May. The blue-headed vireo makes a relatively early migration through the southern part of Wisconsin, typically in late April to early May. Abundant caterpillars on leafing out trees provide a rich source of protein, and the bird’s preference for nesting in conifer trees is due at least in part to the available foliage to conceal nests for this early-arriving species.

Blue-headed vireo, photo by Melanie

In many ways, the blue-headed vireo is anomalous among passerines. Its Latin name (Vireo solitarius) hints at its former common name (Solitary vireo), and these birds live up to their solitary reputation, with males defending wide-ranging territories of northern forestland, up to 15 acres at a time. Additionally, males will build many nests as part of their courtship behavior, with the female finally choosing the male with the best-built nests and most well-defended territory. Perhaps due to the male’s outstretched territory and nest building, the female actually weighs more than the average male, which is rare in songbirds.

Another distinguishing characteristic is the blue-headed vireo’s call note while on the nest, allowing researchers easier detection of these birds on their breeding grounds. This bird’s typical song slightly resembles the red-eyed vireo, but Roger Tory Peterson has called it “more deliberate, softer, and sweeter.” Learning the intricacies of vireo song and plumage can be a launchpad into advanced birding, and as this article writes, the red-eyed vireo—which ceaselessly sings all summer long in eastern forests—is the basis for differentiating vireo songs.

While breeding bird survey routes in northern Wisconsin have shown slight increases in the abundance of blue-headed vireos, their outlook is not all positive. Numerous factors will threaten this bird in the coming decades. At the forefront is climate change. National Audubon’s new Climate Report shows dire predictions for hundreds of North American bird species. An interactive online tool allows you to see the impacts to birds in your zip code, and a look at the blue-headed vireo shows a huge range reduction and movement north (below, photo courtesy of Audubon.org/climate/survivalbydegrees).

This map from Audubon’s Survival by Degrees website shows the blue-headed vireos habitat loss and gain in North America, under a 3 degree warming scenario. Provided by National Audubon Society.

While today, these birds find breeding habitat in the southern Kettle Moraine at 43 degrees north, a predicted warming of three degrees Celsius will result in blue-headed vireos moving at least 17 degrees north—if they can even make it that far.

Another concerning focus of the conservation of blue-headed vireos is the proliferation of an invasive species, the hemlock wooly adelgid. Introduced from East Asia, this bug sucks sap from trees and kills its host within 4-10 years. This bug has devastated eastern forests with hemlock, however; Wisconsin is at the western edge of the range of hemlock, and has yet to report any incidence of hemlock wooly adelgid.

Map of eastern hemlock’s native range, courtesy of USDA Plants Database

The map above shows the range of eastern hemlock in the United States. The gap in the species range across the Midwest may inhibit the spread to Wisconsin, in addition to the Great Lakes buffering its spread. Yet, populations of this bug have been found in western Michigan.

In Wisconsin, hemlock has been increasing since the cutover at the start of the 20th century. The graph below shows the volume of hemlock in the state increasing since the 1980’s, and a continued increase of up to 40% is projected for the next few decades, which could benefit blue-headed vireos.

Graph from WDNR Division of Forestry Report, October 2017

While other coniferous trees may harbor blue-headed vireos, it may be of no consequence unless greenhouse gas emissions are curtailed.

Blue-headed vireo, photo by Skip Russell

Here at Faville Grove, I saw a number of blue-headed vireos in the Ledge Savanna South just last week. I got fantastic up-close looks at these birds as I stood on the quartzite outcrops of the ledge, and the vireos foraged through a hickory tree just a few feet in front of me, apparently gleaning insects. This bird is a true delight on its spring and fall migration (it has a blue head!) and would be a somber loss from our mixed conifer forests of the north.

Written by Drew Harry, Faville Grove Sanctuary land steward

Cover photo by John Sutton

The (ongoing) tale of the elusive Whooping Crane and Goose Pond Sanctuary

On October 2nd, a friend of Sue’s left a message on our phone that he had seen a whooping crane with sandhill cranes about three miles from Goose Pond, about 100 yards from the intersection of Kampen and Harvey Roads, east of Highway 51. He had an excellent look could see that the whooping crane was banded with colored bands.

A sandhill and whooping crane fly overhead. Photo by Arlene Koziol, taken in 2014

Mark checked out the area the next day and finally found the whooping crane about a half mile south of Kampen Road not far from Highway 51 along with 230 sandhills. At that distance, the whooping crane easily stood out.  

The following day, Mark found the whooping crane late morning within a few yards of where it was the previous afternoon. He called Graham and the seed collecting fall employees, and they were all treated to a life bird. At that time the color bands were recorded and reported to the International Crane Foundation. Later that afternoon, Mark was lucky to see the whooper flying about one mile to the east.

A closeup of a captive whooping crane, taken at International Crane Foundation. Photo by Arlene Koziol

Most people know that whooping cranes reached a low of 15 birds in the wild in the 1940s and were close to extinction. This population of cranes nests at Wood Buffalo National Park in Canada and winters at the Aransas National Wildlife Refuge in Texas. Last winter, that population totaled 504 birds including 13 young. We really enjoyed our visits to Rockport, Texas to view the whooping cranes up close.

In 1991, Sam Robbins wrote in Wisconsin Birdlife that there were a few bird whooping crane records from southeast Wisconsin in mid 1800s along with enormous flocks of sandhill cranes. Kumlien and Hollister spoke of “unquestionable breeding to some extent,” however nesting was never confirmed. Sam mentioned that the last historic whooping crane record was from 1878 in Green County that included a specimen.

The next record for Wisconsin was in April 1959 when Owen Gromme observed two birds in Waukesha County. The wild population was still very low and these birds were about 500 miles east of their migration route.

The Robert Lerch family sold Madison Audubon the first parcel of land at Goose Pond Sanctuary in 1968. We remember Robert talking about seeing a whooping crane in back of their house in 1959. The only record of that sighting was Roberts note of the sighting on the back of the passage door for their garage. Robert was a waterfowl hunter and trapper with very good observational skills.

On October 4, 2010 many bird watchers observed and photographed three adult whooping cranes about five miles southeast of Goose Pond at the farmed wetland at Harvey Road and County DM.

Three whooping cranes stand in the shallows. Photo by Arlene Koziol, taken in 2014

A few years after that we spend many evenings looking for the whooping crane that spent the summer at the Anderson Waterfowl Production Area on Highway K, east of Highway 51.

On March 26, 2014 Matt Giovanni, Wildlife Biologist, and Richard Armstrong, Wildlife Photographer were out searching for snowy owls around Goose Pond and both reported spotting a whooping crane. The next day we observed the whooping crane with 10 sandhill cranes just north of the Goose Pond. That evening, Mark was heading out looking for snowy owls and he ran into George Archibald, co-founder of the International Crane Foundation.  

George was out with three Russian crane researchers looking for snowy owls. Mark told them he was searching for a whooping crane. They were surprised to learn of a whooping crane at Goose Pond. The Russian researchers had never seen a snowy owl and one had not seen a whooping crane. Mark and George split up to search a larger area. Not long after that Mark called George and said he found a snowy owl that was in the farmed wetland in Jill’s Prairie. Mark called George and when they arrive they set up their scope and everyone had excellent looks at a whooping crane. Mark said, “I thought you were interested in seeing a snowy owl.” George said they “were interested in seeing a snowy owl and wondered where the owl was that you reported.”  Mark said look in your scope at the whooping crane but look past the crane and you will see a snowy owl! They were thrilled to see a snowy owl and shortly after that two more owls were found including one they photographed from their van at 40 feet.

The International Crane Foundation, the Department of Natural Resources, and Fish and Wildlife Service as part of the Whooping Crane Eastern Partnership has worked from many years restoring a population of whooping cranes in Wisconsin. The International Crane Foundation reported, “The [September 2019] estimated population size is 85 (40 F, 42 M, 3 U). This includes three wild-hatched chicks from 2019. To the best of our knowledge, as of October 1, at least 73 Whooping Cranes are in Wisconsin, 4 are in Michigan, 1 is in Iowa and 1 is in Illinois.”  There is a long story with the reintroduction history with this population that would take pages to cover.

We hope that you visit Goose Pond area in the next month and hopefully you will find a large population of sandhill cranes and one white crane.

Written by Mark Martin and Susan Foote-Martin, Resident Managers, Goose Pond Sanctuary

A whooping crane soars overhead. Photo by Arlene Koziol

Lincoln's Sparrow

Imagining a new world sparrow brings about that old form, a brownish bird smaller than a robin, moving about in flocks; a bird mostly unnoticed and unheralded—not a bird often enthusiastically photographed, or one most people would go to great lengths to see. For those trying to keep track of sparrows, you could witness at least 20 different species in Wisconsin. For those keeping track of sparrows, the subtle variations in coloration, song, and habitat make for interesting study.

Take the Lincoln’s sparrow, for instance, with its overall buffy chest, light brown streaking fading to all white on the breast, a buffy mustache and eye ring, and gray eyebrow. None of these characteristics on its own necessarily makes a Lincoln’s sparrow, though a careful study of the combination of characteristics will reveal a Lincoln’s. The problem, at least for observers, is that the Lincoln’s sparrow rarely makes appearances unobstructed. When it does, the bird quickly drops to the ground at any appearance of a threat. Thus, the Lincoln’s sparrow is one of the more difficult sparrows to observe in Wisconsin.

Lincoln’s sparrow, photo by Kelly Colgan Azar

Breeding pairs occur in northern Wisconsin, mostly in tamarack and spruce swamps. Nesting occurs on the ground in grass or sedge dominated areas. This habitat selection increases the difficulty of seeing this bird during a northern Wisconsin summer, as tamarack and spruce swamps can be incredibly difficult to access in non-winter months.

On these breeding grounds, researchers have discovered that females will select mates based on the quality of their song. Male song with more syllables and phrases, and song that is consistent and long, will heighten female activity compared to males with the opposite song characteristics.

These birds are migrating through southern Wisconsin now, and a week ago, Lincoln’s sparrows were spotted down Prairie Lane at Faville Grove Sanctuary. With the onset of freezing temperatures, Lincoln’s sparrows are actually considered neotropical migrants, making it all the way to southern Central America. At the same time, some birds on the northern edge of their wintering range will spend months in far southern Wisconsin.

Lincoln’s sparrow, photo by Kelly Colgan Azar

Population indices of the Lincoln’s sparrow indicate a stable or increasing population, both continent-wide and in Wisconsin. Close to 1 million acres of tamarack and spruce swamp, and open bog areas exist in northern Wisconsin, providing ample habitat for Lincoln’s sparrows.  

 Written by Drew Harry, Faville Grove Sanctuary land steward

Cover photo by Kelly Colgan Azar