Golden Eagles in NW Wisconsin

The best chance to see golden eagles in Northern Wisconsin is during spring migration.
Photo by Larry Stone.

When Ryan Brady initiated a spring raptor count at the Northern Great Lakes Visitor Center (NGLVC) while a student at Northland College in 1999, his ornithology professor, Dick Verch, had never documented a golden eagle near Ashland, WI.

The first bird Ryan spotted, on the very first day, showed the slightly V-shaped silhouette, small dark head, and dark tail of a migrating golden eagle. Both birders were thrilled! In the second year of the project, Ryan counted almost 50 golden eagles during the spring migration season. In Duluth, the West Skyline Hawk Count spotted 41 GOEA in a single day on March 17, 2022.

(GOEA is the alpha code for golden eagles. Alpha codes are abbreviations of bird names that are employed by ornithologists as shorthand. These codes are established by The Institute for Bird Populations.)

Now a Conservation Biologist in the Bureau of Natural Heritage Conservation, at the Wisconsin Department of Natural Resources, Ryan Brady is still counting and researching birds in Northern Wisconsin. Ryan told me recently that part of the uptick in golden eagle sightings is due to an increasing population. Biologists aren’t completely sure what’s behind the increase.

Golden eagles were not quite as impacted by DDT as other raptors, because they prey mostly on mid-sized mammals like rabbits and squirrels, which don’t accumulate DDT to the same degree that insects, small birds, and fish do. So, the banning of DDT alone can’t explain their comeback. Maybe wildlife protection laws simply mean fewer of them are getting shot? Maybe they are adapting to wintering in our human-dominated landscapes by eating our abundance of turkeys and roadkill deer? Still, humans (collisions with cars and structures, ingesting lead shot, etc.) are their largest source of mortality.

A portion of the increase in sightings may just be a result of looking more. With the proliferation of raptor counts like the one Ryan started, as well as trail cameras capturing the eagles’ presence at gut piles, people noticed more golden eagles. They got excited, started looking more frequently, and now we see a lot more eagles!

Right now, during their spring migration from early March through the first week in May, is the best—and really the only—chance for folks in Northwest Wisconsin to see these big birds near home.

In the winter, some golden eagles hang out in the goat prairies of the Driftless Area of SW Wisconsin and NE Iowa, where they prey on wild turkeys, medium-sized mammals, and carrion. Others spend time in the uplands of the Mississippi River corridor, the Ozarks, and even the Gulf States.

During the summer, golden eagles breed in the Black Hills and Western U.S., but the ones who migrate through Wisconsin are heading to the Canadian Arctic to build their nests. GOEA are also found throughout Europe and Asia on the tundra, in boreal forests, and in mountains. But, as confirmed by Wisconsin’s recent breeding bird atlas, no golden eagles nest in Wisconsin.

On fall migration, golden eagles hit the shore of Lake Superior and follow it around to the west. Counters at Hawk Ridge in Duluth spot dozens in October and November, but the NGLVC is in Lake Superior’s “shadow.”

Outside of this brief window of spring migration, golden eagles typically aren’t here.

So what about the dark eagles we see perched in white pines along our lakes and streams all summer long? Those are immature bald eagles—who take four years to develop their white head and tail.

How can you tell what type of eagle you’re seeing? Season is your first criteria. Golden eagles aren’t here in the summer, while bald eagles of all ages are quite common. Habitat is another clue—golden eagles hunt in the uplands and don’t spend time around lakes and rivers like bald eagles do. Another place you’ll find bald and not golden eagles is eating roadkill along busy highways. Golden eagles do eat carrion, but they are more skittish and prefer to be on the backroads.

How about size? There’s a popular myth that golden eagles are bigger than bald eagles. In fact, their weights and wingspans are similar, and both species exhibit sexual dimorphism in which females are larger than males. Golden eagles have smaller heads—noticeable especially in flight.

There are variations in their feathers, too. Adult bald eagles have the classic white head and tail, of course. Immature bald eagles are mostly dark, with some white mottling. If there is a big patch of white, it will be in their “wingpits.” In contrast, immature golden eagles have white patches on their “wrists” as you look up at them from below. While bald eagles hold their wings flat, golden eagle’s wings are angled up in a slight dihedral—similar to a turkey vulture—but without the vulture’s tipsy flight.

So, when is the best time to see golden eagles in NW Wisconsin? Now! Just look up!

Golden eagles are very similar in size to bald eagles, and can be confused with immature bald eagles who lack a white head and tail. Photo by Martin Mecnarowski (httpwww.photomecan.eu)-Own work, CC BY-SA 3.0, httpscommons.wikimedia.orgwindex.phpcurid=12686118

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Spring: A Season of Disasters

In a little over a week, the Northwoods have gone from being sheathed in ice to swaddled in sunshine. Many of the birch trees who arched over narrow roads and bent their tips clear to the ground on the opposite side have already straightened up. A few remain bowed—their twigs pinned a bit longer by quickly melting snow. The blond wood of fresh wounds glows in the dark forest—those branches will never recover.

The damage from this recent ice storm was not as bad as it could have been. One of the saving graces was that the weather event came on the tail end of a cold winter, and no warmth had begun to tickle the trees into loosening their buds. As buds break, leaves expand, and trees cast off their winter hardiness in preparation for spring, it takes less and less cold to damage them.

During this recent ice storm, the buds and twigs of this beaked hazel were encased in ice. Because the buds were still dormant, they will likely be fine. Photo by Emily Stone.

The rest of March is forecast to be warmer than average. If another ice storm catches our trees off guard, the result may be blackened baby leaves and shriveled flowers. That’s why many of our trees, flowers, birds, and other critters use day length in combination with temperature to gauge whether they are basking in the warmth of actual spring or fool's spring (or one of the other intermediate stages of spring: second winter, spring of deception, third winter, mud season…)

Warm weather followed by a hard freeze in April 2016 meant that this beaked hazel had already flowered—and the flower was damaged by the late frost. Luckily, only the flower was damaged. Leaves were still packed away. Photo by Emily Stone.

Our Northwoods neighbors (humans and otherwise) have lived here long enough to know that even after an early thaw, cold can snap back for a destructive spring visit. We know to plan accordingly. The dinosaurs were not so lucky.

I don’t get to talk about dinosaurs very often. The Museum focuses on plants and animals who are native to the Northwoods. Dinosaurs and sharks are both off the table, much to the chagrin of kids who are well-steeped in Discovery Channel lore of both.

Dinosaurs were here, but erosion—including the glaciers—erased the more recent layers of bedrock or prevented it from even being formed. The rocks we have left in the Cable Area are one billion years and older—too old for fossils.

So, when a headline: “The Reign of the Dinosaurs Ended in Spring” from SciTech Daily, popped into my newsfeed this morning, I was intrigued. How could the season we’re about to enter have hastened the demise of the dinosaurs?

Well, the same way that ice storms in spring cause damage on new growth in the Northwoods.

If the asteroid that hit Mexico’s Yucatan Peninsula 66 million years ago landed in spring, all the critters in the Northern Hemisphere would have been revving up for their most important season of growth and reproduction. Many would have been killed immediately. Tsunamis drowned plants and animals or buried them in sediment. Forest fires flashed across the landscape.

For those that survived the initial impact, dust from the crash dimmed the Sun, reduced plant growth, and stopped food chains in their tracks…right in the middle of baby raising. Seventy-six percent of species—including all non-avian dinosaurs, pterosaurs, ammonites, and most marine reptiles—went extinct.

But in the Southern Hemisphere, animals were preparing for winter. Plants may have been dormant; animals may have been hidden away in burrows or caves. And they weren’t revving up for reproduction. It’s possible that the firestorms blew right over hibernating animals. Having not been roasted, animals recovered faster. Like our tree buds still closed tight in winter dormancy, mammals, birds, crocodiles, and turtles survived.

The other interesting part of this article is how scientists determined the season when this destruction occurred. The evidence came from fish fossils in North Dakota. Earthquakes triggered by the asteroid caused tsunamis and seiches in many bodies of water, not just the ocean adjacent to the impact. The paddlefishes and sturgeons were buried by sediment that got sloshed around by those waves. They died immediately.

While they were alive, though, their bones recorded the seasons just like rings on a tree. Fast, low-density growth in the summer alternated with slower, denser growth in winter. Different forms of carbon accumulated in their bones at higher rates in summer vs. winter. For both markers, the fossil fish’s bones showed rings that were growing faster—but had not yet reached summer’s peak. In other words, the asteroid killed them in the spring.

What lessons can we learn from the dinosaurs’ demise? There are many, I’m sure. The comfort I’m taking from their story today (even as snow melts at a record pace) is that the quiet dormancy of winter is not all bad.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Ice Storm: Beauty and Destruction

“Isn’t it beautiful?” I exclaimed over and over this past week as sunlight glinted off the ice-covered trees. The glassy twigs outside my bedroom window distract me each morning, and I find myself gazing into their patterns and sparkles while I should be getting ready for work.

Of course, it’s also a terrible beauty that has wrought destruction on our forests, created deadly challenges for wildlife, and become a headache for the people who manage, maintain, and use our many roads and trails. (As well as for the people who had a branch spear through their roof.)

“A mark of true intelligence is the ability to hold competing thoughts or ideas while striving to better understand both,” wrote my philosophical friend on her Facebook page this week. It felt especially appropriate as my mind swirled trying to imagine all the impacts of this storm. Clearly, it’s beautiful. Clearly, it’s destructive. What are the positive and negative impacts, both now and into the future?

The immediate impacts on our trees are visible everywhere, while the long-term effects remain hidden. Gracefully bent birches form archways and tunnels over our roads and trails. Some are flexible enough that the tips of their twigs are now frozen to the ground. Some broke off completely.

The bent trees may straighten up over the next few months; or they may not. A Mr. Ashe, in a 1918 issue of the Monthly Weather Review wrote, “a young stand ... bent into an inextricable tangle ... the signs of this storm will be written in this stand for a century ....’’ Many of the straightened trees should be fine for lumber, but bent ones will be difficult to harvest and sell. Some smooth-barked young hardwoods may exhibit “stretch marks” on the outside of their bend.

What determines whether a tree will bend or break? In part, it’s the structural characteristics of the species—wood density, flexibility, branching structure, height-to-diameter ratio, and surface area of the twigs and needles available to catch heavy ice. When you cook asparagus, do you also find the place where the stem turns from tender to woody by bending it until it snaps? I imagine the force of the ice snaps trees in the same way. The breaking point may also be determined by the characteristics of older wood vs. younger, or a weak spot caused by decay, a knot, or other deformity.

The death of an individual tree is sad, of course, but the impacts on the forest as a whole are not all bad. Light gaps created by this storm will release saplings in the understory, and new trees will grow quickly to fill the gap. This storm is a rare opportunity for them—if they aren’t buried under debris.

Dead trees are an opportunity for insects and fungi—and therefore for woodpeckers and other wildlife, too. Paul Cigan, Forest Healthy Specialist at the Wisconsin DNR, sent me a long list of the most common fungi that might colonize trees killed or damaged in this storm. Happily, oak wilt wasn’t one of them; the beetles that transport it being out of season. Also happily, chicken-of-the-woods was on the list—one of my favorite edible mushrooms. “Trees are more alive when they are dead,” is a favorite quip of ecologists while they imagine the extensive network of fungal hyphae, bacteria, and insect tunnels inside a snag.

Where trees are damaged but not killed, the wounds left by ripped branches may develop into cavities. Dead trees rot evenly, so hollows only form in living trees, because the outer wood stays intact while heartwood rots away. Tree cavities for nesting are a limiting factor for many birds, including bluebirds, sapsuckers, flickers, tree swallows, red-headed woodpeckers, wood ducks, and American kestrels. The wounds from this storm may yield more chicks in the future!

In general, the impacts on wildlife are negative in the short-term, but positive in the future. Several people told me of seeing ruffed grouse confused and forlorn, walking hungrily across the crusty snow in the storm’s aftermath. The ice now prevents them from seeking warmth and protection from predators by diving into snow roosts. The ice has also encased the aspen buds they love to eat in a hard, slippery shell. Not even the fringe of pectinations they grow on their toes—a combination of snowshoes and Yaktrax—could help them initially. They had to turn to starvation food, like the acidic fruits of highbush cranberry.

Just a few days later, though, south-facing trees had captured enough sun to melt ice off the twigs, and flocks of grouse were spotted taking advantage of this microclimate to find food. Grouse and other birds might struggle again this spring and coming fall, though, since many of the cylindrical catkins that hold birch, hazel, and alder flowers (and then become seeds) have snapped clean off.

These birch catkins were encased in ice and glued to the twig next to them. Then their stem broke. They won’t be producing flowers to attract warblers or seeds to feed grouse. Photo by Emily Stone.

Deer are struggling through the crusty snow, of course—that’s an issue every year—but the weighted branches of pines are now within nibbling height, bringing them a food source that had previously been out of reach. My friend Jan even spotted a deer browsing on the twigs of a birch crown that had crashed to the ground.

Five days after the storm, as I snapped into my skis for a tour of the damage, Metro Maznio pulled up on the groomer. Metro has been in the area since the 1950s. I asked if he’d ever seen a storm like this, and he shrugged a “yes.” He remembers some trees taking months to straighten, and seeing others permanently arched. Ice storms aren’t unprecedented here, but current models of climate change suggest that we’ll be seeing more of them…their beauty AND their destruction.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Poop (a scientific exploration)

A few weeks ago, as I was watching the flocks of redpolls, goldfinches, and chickadees swoop between hemlock boughs and my one little feeder, I noticed that the hemlock needles had spots. Could it be snow? No, not after one of our long dry spells this winter. Since the plow pile hadn’t yet grown to enormous heights, I was able to nose in close to the trees for a better look.

As I examined the small, whitish, cylindrical lumps frozen to the twigs, first I started chuckling to myself, and then I went to grab my camera. The trees were covered in little nuggets of redpoll poop—of course I had to get some photos!

Little white nuggets of ammonium urate are frozen onto the hemlock twigs near my bird feeder. Photo by Emily Stone.

You know, I probably say the word “poop” more than your average three-year-old. During presentations about my Natural Connections books, I’ve been tempted to ask my adult audience if someone would count the number of times I say “poop.” Why does it come up so often? We’ll, for starters, poop is essential to the flow of nutrients in nature.

For example, inside the leaf of a pitcher plant lives a community of critters. When an ant or other food item drops in, fly larvae, mosquito larvae, and midge larvae all work together to break it down. Bacteria and other microorganisms help, too. At each step in the food chain, a community member eats something, takes what they need, and poops out the rest. Their poop might still contain valuable nutrients that are useful to another critter. Eventually, the nutrients take a form that the pitcher plant itself can absorb directly through its leaf.

Poop comes up when I teach kids, too, of course. Almost every lesson I present starts with a review of the food chain. Food chains really do make the world go ‘round. After Sun, plants, herbivores, omnivores, and carnivores, I like to include scavengers and decomposers. Since both of these groups eat dead stuff, I had to find a kid-friendly way to differentiate them. My solution: scavengers have regular poop, and decomposers poop out soil! This is shorthand for the fact that decomposers break their food down into its chemical components—nutrients like nitrogen and carbon—that are essential for plants.

Poop is also valuable for studying wildlife. When I was in Alaska in 2018, I tagged along with a few different research projects, and two of them were gleaning information from the scat of snowshoe hares. “We can’t just walk out there and say ‘hey animals, come out, I want to count you,” explained Denali National Park’s wolf technician, Kaija Klauder, to a group of high school students from Anchorage who were attending a summer science camp. “Luckily,” she continued, “all animals poop, and that’s awesome for science.”

My student buddy and I counted all the Skittle-shaped, sawdust-filled hare pellets in a one-foot radius sample plot. The 200 plots our group sampled that day would get plugged into a spreadsheet. With a little bit of math, scientists could estimate how many bunnies must be in the area in order to make that many poops.

Later that summer, I joined Claire Montgomerie, a graduate student from the University of Alaska Fairbanks, doing research in the Brooks Range. She was trapping the snowshoe hares to count their population numbers, and then also drawing blood to learn about body condition and stress levels. In addition, we filled little whirl-top bags with fresh hare scat from under the wire mesh of the trap. Chemical analysis of the blood would give a seasonal average of body condition, while scat analysis might reveal a snapshot just from the hare’s stay in the trap.

Poop also comes up quite a bit while doing animal tracking. From seed-filled bear scat to hairy wolf turds, and even the frass of caterpillars and leaf miners, animal poop can tell us a lot about who lives where and what they are eating. Little piles of worm castings can even clue us in to when these non-native wigglers have moved into our woods.

So, as a naturalist, I don’t think it’s weird that I spend time looking at, thinking about, and teaching about poop. I don’t even think it’s weird to Google it.

And today, I’m glad I did! I’ve always been taught that the white part of bird poop is their version of urine. It is concentrated uric acid that goes straight from the kidneys to the cloaca because birds don’t have a bladder. Water is reabsorbed in the cloaca, which reduces the need for birds to drink. It gets excreted at the same time as their feces—the dark parts of bird poop. At least that’s the conventional wisdom.

In 2019, a researcher following his curiosity and a hot tip from an ornithologist, analyzed poop from six varied species of birds. Instead of uric acid, he found ammonium urate, struvite, and two unknown compounds. The resulting hypothesis is that birds do turn their wastes from protein digestion into uric acid, but that bacteria in their cloaca break down the uric acid into other materials before it leaves their body. So much for conventional wisdom!

That doesn’t explain why I suddenly saw so much bird poop on my trees, though. That occurrence has several causes. First, I have many more birds than usual at my feeder. The repolls have more than tripled my population counts! Second, the cold weather meant that birds were eating a TON in order to stay warm. Eat more, and you have to excrete more, too. Finally, birds tend to poop during lift-off. This lightens their load and makes flying more efficient. So, when they take off from my hemlock boughs, they leave a little package behind. In the sub-zero temps of those weeks, the poop froze to the needles and built up over time.

Next time your favorite three-year-old starts talking about poop, maybe you’ll have to join them in some scientific discourse.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Tough Little Birds

As days lengthen and the sunshine strengthens, I start dreaming ahead toward spring.

We all have our favorite signs of the new season, I’m sure, and one of mine is hearing the sweetly whistled trill of a yellow-rumped warbler, and then catching a glimpse of their “butter butt” as the namesake patch of color is revealed. Yellow-rumped warblers are some of the first of our summer breeders to arrive and often seem in no hurry to leave. That’s because they don’t need to migrate all the way to Central or South America to find insects to eat. Instead, they survive the winter by nibbling on the fruits of wax myrtle trees common in the southeastern United States.

This yellow-rumped warbler was preparing for fall migration while the weather was still warm in September 2019. Photo by Emily Stone.

Still, we don’t expect to see them by the time temperatures plummet and blizzards blow in. That’s why Museum volunteer Jan Sharp was both surprised and worried when she spotted a yellow-rumped warbler in her yard in Clam Lake, WI, on December 4, 2021. An avid birder, Jan started posting updates and observations to the Chequamegon Bay Birding Facebook group right away. Her posts revealed a mix of hope and trepidation for the bird’s predicament.

On December 21, Jan made detailed introductions on Facebook, and explained her efforts to help the warbler survive:

“This is Myrtle. She's a yellow-rumped warbler. She's not supposed to spend the winter here. She's supposed to be only as far north as St. Louis. She's a first-year female, and I guess with the warmish fall we've had, she missed the memo about migration (or is sick or hurt). She likes the nuts and berry suet, and sunflower seed (shelled).

“She's gutsy, and smart, and skulky. And I've put little grass-lined huts out for her, too (I doubt anything will use them). I doubt she'll make it through the winter, especially if we have more polar vortexes. But I admire her spunk and will to live. Pretty amazing creature. (And she's a new record on the Clam Lake Christmas Bird Count!)

This is Myrtle, a young, female, yellow-rumped warbler who struggled to survive winter weather far north of her typical range. Photo by Jan Sharp.

 

Over the course of several weeks—and several extreme temperature swings—Jan kept us all posted on Myrtle’s feeding schedule, the level of fluff in her feathers, the condition of her tender feet, and her interactions with other birds. Then, on January 20, the news came,

“Sadly, I believe Myrtle is no longer with us. I have not seen nor heard her all day. She had a shaky foot yesterday morning and I felt it was a red flag as the cold seemed to get to her feet first. And with the -19 degrees F this morning, I think the cold weather finally took its accumulated toll. What a survivor. I celebrate her grit, her brains, her persistence, and her resilience.”

Meanwhile, as Myrtle was failing in her battle against a Northwoods winter, huge flocks of redpolls were moving in. These little brown birds have been whirling under bird feeders across the region in much higher numbers than usual. It’s an irruption year for several species of northern seed-specialist birds. (No, not an eruption, although sometimes I do imagine a volcano of boreal forest in Canada spewing forth a feathered ash cloud.)

A bird irruption, according to the Cornell Lab of Ornithology, is a “movement of northern-wintering species to the south in years of low food availability.” When trees produce fewer seeds in Canada, the grosbeaks, siskins, crossbills, waxwings, finches, and nuthatches come here to eat.

This year, redpolls are the most common out-of-town guests at my feeders. With a jaunty red cap and rosy breast to brighten up their brown and white stripes, they are very welcome. For weeks, if not months, I’ve been watching them flutter over the snow surface scooping up the delicate seeds of birch. Now, with the blizzard, they’ve come to my feeder and are nibbling at sunflower hearts right along with the chickadees.

Common Redpoll on a tree branch in winter, Kenai National Wildlife Refuge, Alaska
By Lisa Hupp/USFWS - https://www.facebook.com/photo?fbid=251704623743122&set=a.221378263442425, Public Domain, https://commons.wikimedia.org/w/index.php?curid=114623684

Even as temperatures drop again, I’m not worried about the comfort of these little friends. Myrtle may have needed our concern, but repolls are built for the cold. Remember, the Northwoods are south for them! Each autumn, just when we’re pulling sweatshirts and down vests out of our closets, the birds increase their insulation. Redpolls grow about 31% more feathers by November. Then they take a hint from ruffed grouse—by diving under the snow to stay warm. Their tunnels can be over a foot long and four inches under the surface. For such a tiny bird, that is impressive!

Even while buried in the snow, redpolls can keep eating. There’s a pocket in their neck where seeds collect and then trickle down into their stomach. These seeds fuel the bird’s metabolism and allow them to maintain their body temperature without a mid-nap trip to the refrigerator. With all these adaptations, tens of millions of redpolls survive in their rugged homelands surrounding the Arctic Ocean at the top of the globe, and we get to enjoy their visits every few years.

Myrtle was impressive because of how long she survived in the cold against all odds, without the right adaptations to get her through. Redpolls are equally impressive because their adaptations are built to help them thrive in those same, challenging conditions. They are all tough little birds.




Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.