Fishers Looking For Love

My skis chattered over rough snow on the Valhalla Ski Trails that are perched on the spine of the Bayfield Peninsula. Several loops zoom from dark stands of pines through the lacy twigs of hardwood forests. The groomer had been out earlier that day, but in places where the previous day’s warmth had turned icy overnight, the surface had crumbled.

Still, the snow had enough give that when my ski buddy shouted “Check out these tracks!” I could snowplow to a stop and go back to look. Around the office, we’ve been asking each other the question, “If you could instantly be great at any Olympic sport, which would you choose?” Several people have mentioned skiing, but that doesn’t appeal to me. I prefer to ski slow enough that I can stop and look at tracks.

Male fishers travel widely in search of females in late winter and early spring. This one left a 1-2-1 loping pattern in soft snow at the Valhalla Ski Trails. Photo by Emily Stone.

These tracks went loping off through the forest in a winding trail. Unlike a wolf or a lynx, who usually walk or run in an even pattern of left, right, left, right, this Being had made groups of three or four big tracks separated by longer intervals. Each track showed five toes with pointy claws. This is the classic 1-2-1 lope pattern of a fisher. One front paw landed first, by itself in the back of the group (1). Then the other front paw and one hind paw landed side-by-side in the middle (2). Finally, the last hind paw left a single track at the front of the group (1).

From the depth that the toes had clawed into the snow, and also the smooth surface on the bottom of the tracks, we determined that this big weasel had been wandering around yesterday afternoon or evening, when the snow was still soft. Those long claws, when used in combination with rear ankle joints that can rotate 180 degrees, allow fishers to climb down trees headfirst!

Female fishers may be climbing trees this time of year as they look for a good place to have their young. Hollow trees are common den sites, as are rock crevices, slash piles, abandoned beaver lodges in dry ponds, and old porcupine dens. Inside the female, eggs fertilized last spring have only just begun to develop. A few kits will be born—blind and helpless—in late March to early April. Just a week or two later she will come into estrus and leave the den briefly to mate, but the new embryos won’t develop further until next February. Meanwhile, she will spend four months caring for the kits.

We continued skiing through the mature forest, admiring big trees and snags that the Forest Service has left for wildlife habitat. Fishers prefer closed canopy forests with lots of fallen logs. The cutover era, when most of Wisconsin’s forests were logged and then burned, had a devastating impact on fishers. Not only did these events remove their habitat, the influx of people led to overharvesting fishers for their fur. Fishers were absent from Wisconsin by the early 1900s.

I’ve heard a story that it was foresters who lobbied for the reintroduction of fishers because the number of porcupines had increased so much that they were nibbling the bark off too many trees. Porcupines are well-defended against predators, but the low, slinky posture of fishers allows them to dart in and attack a porcupine’s face repeatedly. Once the porky is incapacitated, a fisher will flip them over and access their unprotected belly. Fishers also eat squirrels, and compete with lynx for snowshoe hares. When fishers eat mice and voles, spores from truffles and other fungi in the preys’ stomachs also pass through the fisher’s digestive tract and may be dispersed far and wide.

Despite their name, fishers don’t really eat fish. The word seems to come from a European term “fitch,” which refers to a similar animal on that continent. The ancestors of fishers likely migrated to North America from eastern Asia between 2.5 and 5 million years ago. Sometimes called fisher-cats, they are not felines, nor have the rumors that they commonly eat cats stood up to scientific inquiry.

On the far side of the ski trail loop, we coasted past another loping line of fisher tracks, almost certainly made by the same animal. Early spring is when male fishers travel widely in search of mating opportunities. I often see their tracks in the softening snow as they tour their 9-15 square mile home ranges that overlap the smaller territories of several females.

Whether the Wisconsin DNR decided to reintroduce fishers for porcupine control, or just because they belong on the landscape, the recovery effort that began in the 1950s was successful. By the 1980s there were enough fishers to allow trapping again, and today their population in the state is estimated at over 10,000. Even so, I rarely see these dark brown weasels, except on my trail camera, or in my imagination as I watch their tracks lope off into the snowy woods.

While there are an estimated 10,000 fishers in Wisconsin, I rarely see them in the wild. Trail cameras are a much easier way to catch a glimpse of one. Photo by Emily Stone.

Emily’s third book, Natural Connections3: A Web Endlessly Woven, is 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. Our Winter Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

 

The Elusive Lynx

I stared open-mouthed in disbelief at the cat crossing the neighborhood street in front of my new house in Silver Bay, MN (I’ll be moving up full time in 2027). Trotting purposefully on long legs, with a body almost three feet long, this was no housecat. “Bobcat!” I exclaimed, eyeing the black tip on their short tail and dark blotches on gray-brown fur. Bobcats are common in Northern Wisconsin where I’ve been living for the past 15 years, and are often spotted around homes and roads, so that was the most likely identification my startled brain could find.

You can view the video on my Facebook or Instagram.

But as the cat climbed up the pile of dirty snow on the curb and into my neighbor’s yard, the size of their huge, furry feet came into full view. That, along with long black ear tufts visible against the white, confirmed their identity: Canada lynx.

In this still frame from a cell phone video, you can see the short, black-tipped tail, huge foot and striking black ear tufts characteristic of a Canada lynx. Photo by Emily Stone.

I’ve been lucky enough to see lynx before—once crossing the highway on a road trip across Canada, and again in Alaska when I helped a crew of biologists recover the body of a collared lynx who had died. But lynx are known to be elusive, solitary creatures who travel mostly by night in the tangled spruce-fir forests and conifer swamps of the far north.

While a small number of lynx once called Northern Wisconsin home, they’ve never been common, and declined rapidly as logging changed the forests, the winter snowpack thinned, and more aggressive bobcats took over. The last confirmed sighting in the state was in 1992, and was likely a visitor from Canada.

Minnesota is a different story. With an estimated 100-300 individual lynx in the state at any given time, Minnesota has the third largest lynx population in the U.S., after Alaska and Maine. And most of the lynx sightings occur in Cook and Lake County, where Silver Bay is located. In fact, a couple of different population maps from the DNR seem to indicate that the Superior National Forest just uphill from Silver Bay has relatively high numbers of lynx. It’s not hard to understand why—the ski trails I’ve visited up there are all crisscrossed by abundant snowshoe hare tracks. Hares make up 90% of a lynx’s diet, so good hare habitat equals good lynx habitat.

Figure 13. Lynx winter-specific occupancy probabilities (medians). Grid cells are 5×5 km and encompass Superior National Forest and designated lynx critical habitat in Minnesota, USA From:  Summary of the Superior National Forest’s Canada lynx (Lynx canadensis) DNA database and population monitoring 2024. LINK 

You can see the large hind feet of a snowshoe hare in these tracks as they cross a ski trail. Lynx also use large feet to carry them across deep snow—in pursuit of hares to eat! Photo by Emily Stone.

This is what a snowshoe hare's foot looks like from the bottom! Big and hairy! Photo by Emily Stone, taken while assisting researchers in Alaska. 

When hare populations go up, lynx numbers go up, too. When the bunnies crash headlong into a population low, lynx follow. Hungry humans all across the North have been aware of this cycle for hundreds of years, since hares were a staple in their stew pots. The lynx-hare cycle has been highlighted in ecology textbooks since 1942, when British ecologists Elton and Nicholson did a quantitative analysis of lynx numbers in the fur trapping records of the Hudson Bay Company. (Read about some theories explaining why this happens here.)

But the lynx population in Minnesota stopped following the hare cycle closely in the 1980’s. Now there’s just a small bump in the lynx population a year or two after hare numbers peak. Ironically, it may be the recovery of other mid-sized predators, like bobcats, fishers, coyotes, and foxes that has made it tougher for lynx. These other carnivores also love to eat snowshoe hares, but are able to pursue a much more varied diet when the hare numbers are low. Lynx aren’t nearly as flexible. They really shine when super deep snow slows their competition down.

Lynx feet can be 4” round, and heavily furred, which helps them stay on top of deep snow. This foot belonged to the lynx in Alaska who we recovered after their radio collar put out a mortality signal. Photo by Emily Stone.

Scientists with the Minnesota DNR, the University of Minnesota Duluth’s Natural Resources Research Institute, and the U.S. Forest Service are all working to figure out how many lynx there are each year, how well they are surviving, and how forest management can help them thrive. They are gathering hair and scat samples to identify individual lynx by their DNA.

My fiancé and I watched the lanky cat lope toward a forest that slopes down toward Lake Superior. It’s breeding season for lynx—could this be a male out searching for a mate? We crossed the street to look for tracks. Their furred feet float so well that not even a scuff could be seen on the crusty snow. I didn’t think to look for hair, but later I reported the sighting through a Minnesota DNR portal. What a thrill for my new neighborhood to be a dot on their map!

Source: https://www.dnr.state.mn.us/nhnrp/lynx_sightings.html 

Emily’s third book, Natural Connections3: A Web Endlessly Woven, is 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. Our Winter Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Is the Sun Setting on Evening Grosbeaks?

The last leg of my morning commute takes me from the Museum’s parking lot to the front doors. Though short, this walk is often filled with birdsongs. Chickadees can always be counted on, blue jays shout their alarm, and house finches twitter from the neighbor’s cedar trees in the spring. One morning last week there was a chorus of sweet, arrhythmic calls coming from the hedge of boxelder trees by the street.

It was a gray morning, with just enough sun to silhouette the trees. When I stopped moving, their fluttering revealed a dozen or so robin-sized birds. As I watched, they plucked at the maple-like boxelder seeds in their large, pale bills. Discarded seed wings littered the snow beneath the tree. Squinting from a new angle, I could just make out the bright yellow bellies, black-and-white wings, and yellow foreheads of the male evening grosbeaks in the group. The females would have blended perfectly with the gray sky if it weren’t for black-and-white on their wings.

Male evening grosbeaks are bright yellow! Photo by Emily Stone.

Despite the poor light, I was thrilled! It’s so nice to see their sunny yellows when our local goldfinches have gone drab. In 2023, flocks of a hundred or more evening grosbeaks were spotted at many feeders in the Northwoods—but not mine. This winter, I’ve been watching jealously as my neighbors proudly post photos of small groups of grosbeaks visiting their feeders every few days. My feeders are too small for these big birds, but this tangled mess of boxelder fits their bills.

Evening grosbeaks are colorful members of the finch family. They got their name not because they are the color of the setting sun, but because English settlers thought the birds only came out of the woods to sing at sundown. French settlers reportedly gave them the more accurate name of le gros-bec errant, the wandering grosbeak. These bright birds travel widely toward the best food sources in movements known as “irruptions.”

In winter, evening grosbeaks are attracted to the large seeds of deciduous trees like maples, ashes, and boxelders. In the summer, they seek spruce budworms—the destructive caterpillars of a little brown moth—to feed their chicks. Grosbeaks are so good at detecting spruce budworms (which also feed on balsam fir trees) that an influx of the birds is often humans’ first clue to the start of an outbreak.

But cycles of natural budworm outbreaks and shifts in how much humans try to control outbreaks through aerial spraying, now impact how much baby food grosbeaks have access to from year to year, and decade to decade. It’s not good. According to the Finch Research Network, evening grosbeaks have declined by 92% since 1970. The causes of this decline are not fully understood, but likely stem from changes in both their summer and their winter food sources.

Back in the 1800s, evening grosbeaks were mostly a western species. In the early 1900s they started to move east, mostly in winter, probably due to the marked increase in the popularity of boxelder as an ornamental tree. Then the 1970s saw extensive spruce budworm outbreaks. The dramatic increase in both their summer and winter food at this time may have meant that evening grosbeak populations were unusually high at the start of the period of decline.

Logging, too little or too much management of budworm, and diseases like West Nile likely ended the grosbeaks’ period of abundance. It doesn’t help that evening grosbeaks are the species most commonly killed in window collisions, and they are also hit by cars in high numbers when flocks descend to the roads for salt. They may even be a victim of their own success as the budworms that grosbeaks love to eat sometimes end up destroying the birds’ breeding habitat.

In the 2016 Landbird Conservation Plan produced by Partners in Flight, the evening grosbeak was cited as the steepest declining landbird in the continental United States and Canada. They aren’t listed as endangered yet but have been designated a “species of special concern.” Scientists have come together in an Evening Grosbeak Working Group to fill the knowledge gaps across priority areas like diet, causes of death, migratory and population dynamics, habitat, and climate change.

Among other things, scientists are outfitting grosbeaks with satellite and radio transmitters and colored leg bands to help track their movements. The same MOTUS towers that I wrote about for tracking saw-whet owls in Bayfield Country are also recording radio-tagged grosbeaks! Up in Sax-Zim Bog in northern Minnesota, 75% of grosbeaks who scientists outfitted with solar-powered satellite tags stuck around the spruce-fir forests of this Important Bird Area, while the rest of them journeyed off in all directions.

How can you help? If you see grosbeaks, post your photos to iNaturalist or eBird where scientists can use them as data to determine where the birds are and what they are eating. Or if you’re lucky enough to see one with a colored band, report it to the USGS Bird Banding Laboratory. Learn about ways to prevent birds from colliding with your windows from the American Bird Conservancy. Keep cats inside. Keep your bird feeders clean and take them down if you notice sick birds. Support the Finch Research Network and other conservation organizations with your donations.

Together, networks of scientists and legions of bird-lovers are working to make sure that the Sun isn’t setting on evening grosbeaks.

Emily’s third book, Natural Connections3: A Web Endlessly Woven, is 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. Our Winter Calendar is open for registration! Visit our new exhibit, “Becoming the Northwoods: Akiing (A Special Place). Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.