Thursday, September 17, 2020

The Ash Tree Mystery

I’ve always loved a good mystery. It probably started with The Boxcar Children books. Those mysteries aren’t about murders. They contain just the right amount of delicious suspense without being scary, and often I learned something from those books outside of my normal experience, too. The mysteries I read these days are about nature, whether in a book or in the wild. And recently, I’ve been seeing something mysterious in the woods. 

Now that the cold weather is triggering trees to draw green chlorophyll back into their twigs, their yellow and orange pigments—always present—are suddenly visible. After swamp maples and other occasional stressed out trees, black ash trees are the first to show fall colors. Black ash swamps are currently a warm shade of gold, and provide a cheerful place to gaze while the clouds are gray and heavy. In among those sunny leaves, though, are scraggly, dark brown clumps about the size of a softball that I’ve puzzled about off and on for years. 

Black ash swamps show their colors in early fall. Photo by Emily Stone.

Are they clumps of seeds? Well, no. Ash seeds do hang in clusters, but they take the shape of little, oblong samaras—winged seeds like maple helicopters—that change from pale green to straw-colored (not dark brown) as they ripen. 

Are they clumps of dead leaves? It’s not that, either. Sometimes I do see ash trees where their leaves haven’t fallen off completely, but there aren’t scraggly clumps left behind; there are just elegant, yellow-green leaf petioles. 

On a recent kayak trip down the Namekagon River, I spotted an ash tree with the mysterious clumps, and since I was paddling next to a forester, I pointed them out. “Well, you know,” she said, “individual ash trees are either male or female.” I didn’t know that! We reasoned that since the female trees would be producing the seeds—which look different than these clumps—these would most likely be the male flowers. Now I had a lead, and I brought it back to Google.

At first, the photos of male ash flowers that popped up just looked like small, maroon pompoms tipped with pollen, and that wasn’t helpful. But as I scrolled through the images, a brown clump appeared, and I followed it through to a blog post about ash flower galls. Of course. I should have guessed. The clumps are caused by critters!

The male flowers on black ash trees are transformed into scraggly brown masses by a microscopic mite. Photo by Emily Stone. 

Ash flower gall mites (Eriophyes fraxinivorus), look like translucent walruses. At only 2/100 of an inch long, however, they are not visible to the naked eye. All winter, fertilized female mites hang out on ash twigs, sometimes even crawling inside the fuzzy brown scales that protect the flower buds like a warm winter jacket. Come spring, the mites feed and lay eggs on the developing flowers. As with any gall, the feeding action stimulates the plant to grow around the interloper. On a goldenrod stem, for example, a fly larva creates a globe-shaped gall. 

These ash flower gall mites cause a much more messy reaction. Under the mite’s influence, flower stems grow longer than normal, and even fuse with their neighbors. Everything curls, twists, branches and fringes, and forms a broccoli-like mass. Several generations of baby mites called nymphs find food and protection within the gall over the course of the summer. 

In September, the green gall turns into a woody, brown clump, and suddenly I start noticing and pondering this mystery all over again. Once dry, the galls may remain on the tree for a couple years, and can be unsightly, but won’t cause the tree much harm. 

Galls are a widespread example of a symbiosis, where two different species have a close living relationship. I’ve written about oak apple galls, goldenrod galls, willow pine cone galls, willow rose galls, and aspen leaf galls—they’re all fascinating! 

So, mystery solved, and yet another story about a gall added to my list. Maybe The Boxcar Children should add this one, too, and call it: “The Ash Tree Mystery.”

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.

Thursday, September 10, 2020

Little Packets of Fatty Goodness—New Research

On a humid morning in late July, I found myself hiking the steep trail to St. Peter’s Dome with an energetic family and a swarm of mosquitoes. I remembered fondly back to my early spring hikes—when the wildflowers were in full bloom and the bugs had not yet hatched. 

I interrupted my own reverie when I spotted a little green capsule dangling among the graceful leaves of a large-flowered bellwort. Last May, I’d stopped several times to photograph this plant’s sunny yellow petals, and here was the next step: a pod full of seeds. 

The seams on the 3-sided pod were already bursting, an action which botanists call “dehiscence.” As I cradled the opening pod, tiny seeds landed in my palm. With cream-colored faces and tiny white wigs, they could be the start of some miniature George Washington dolls. Actually, though, the wigs are little packets of fatty goodness called elaiosomes. I like to describe them as donuts for ants. 

The seeds from large-flowered bellwort are topped with appendages to attract ants. They also remind me of George Washington in his wig. Photos by Emily Stone. 

Back in 2013, when I first learned and wrote about elaiosomes, the most popular hypothesis was that the flowers were bribing the ants to carry their seeds into anthills, where they would be discarded on a compost heap—well-fertilized and out of the reach of hungry birds and raging wildfires—to grow. Other hypotheses are being tested as well. Recent research highlights other nuances of the relationship between ants and plants. I called three of the scientists doing that research to find out more. 

Dr. Chelsea Miller, who recently earned her PhD from the University of Tennessee in Ecology and Evolutionary Biology, did some field work that sounds lovely. First, she went out in early spring, when all of the Trilliums were gorgeously in bloom, and flagged 30 individuals of a few different species. Then, she went back in late summer when their seeds were almost ready to dehisce, opened the pods a tad early, and put the seeds out on a “seed depot,” which is a fancy way to say a place that ants can get to that also allows scientists to keep an eye on the seeds. Then she sat down, set a timer for an hour, and waited. 

Chelsea Miller studied how ants disperse the seeds of Trillium flowers for her PhD research. Provided photo.

As you can imagine, Chelsea saw more than ants. “I had a lot of quiet time to myself in the woods,” she told me. “It’s kind of a gift.” An oblivious deer wandered by, interesting birds grew used to her presence, and once a bear showed up. Chelsea also saw (about half the time) one or more ants arrive at her depot, pick up a seed by the grippy elaiosome, and carry it off. She then followed the ant until it dropped the seed or arrived at its nest, and measured that distance—usually only a couple of meters or so. 

Chelsea observed that seeds from common and widespread species of Trillium seemed to attract more attention from ants than their more rare Trillium cousins. Using mass spectrometry, she confirmed her hypothesis that the elaiosomes of the widespread species contain more of the nutritious oleic acid than the rare species of Trilliums she tested. The conclusion is one any entrepreneur can understand: flowers are more successful when they make more desirable donuts for ants. 

The capsule from a Trillium flower splits open to reveal brown seeds with white elaiosomes. These attachments provide ants with nutrients in exchange for transport, but new research points to additional complexities in that relationship. Photo by Emily Stone.

We can watch as an ant removes an elaiosome and either eats it or feeds it to the colony, but what if the ant is adding or subtracting things from the seed that we can’t see? Dr. Chloe Lash, who just earned her PhD from the same lab as Chelsea, studied how ants impact a seed’s microbiome as they handle it. Microbes are living things like fungi and bacteria who we can’t see with our naked eye. 

In order to do the study, Chloe made a pool of the microbes, extracted DNA, and put the samples through a machine that sequenced the DNA. This told her who all was there and their relative abundance. She analyzed the microbiomes of bloodroot and wild ginger seeds straight from the seed pods; after ants had handled them; and after she had removed the elaiosomes herself. As predicted, the microbiomes changed. Ants not only removed the elaiosomes, they also removed several potential pathogens from the seeds and altered the entire microbial community.

The seeds of bloodroot contain elaiosomes AND a microbiome of fungi and bacteria. After an ant removes the elaiosome, the microbiome is altered as well! Photo by Emily Stone.

One day, while Dr. Kirsten Prior, now a professor at Binghamton University (SUNY), was watching her own seed depots for signs of ants, a slug crawled by and scraped the elaiosome off one of the seeds. At first she was just annoyed at its interference, and then, as science often works, she decided to study the slug. In Europe, native slugs eat whole seeds to get at the nutritious elaiosome, and then poop out the seeds where they can grow. This non-native slug who Kirsten observed just stole the donut and left the seed where it lay, interrupting its dispersal. 

Why should we care about nefarious slugs? Ants disperse the seeds of 30-40% of our understory plants, including many of the beautiful spring wildflowers who are disappearing. There are other invasive villains out there, too. Non-native earthworms seem to displace ants. In other places, non-native ants may be changing how and which seeds get moved around. 

During the interview, Chelsea told me that “The most exciting thing is how much we don’t know!” These scientists have made interesting discoveries about relationships that are integral to our ecosystems—and that impact our favorite wildflower woods. They’ve also made it clear that we have much more to learn. I, for one, learned that sometimes it is worthwhile to take a walk in the woods…even during mosquito season.

Nodding trillium seed capsule. Photo by Emily Stone.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.

Thursday, September 3, 2020

Award Winner: Beaver Costume

(I’m thrilled to announce that this article won 2nd place in the Newspaper/Family Participation-Youth Outdoor Education category of the Outdoor Writers Association of America’s 2020 Excellence in Craft Contest! It’s a little bittersweet to post it just as school begins, since our MuseumMobile lessons are moving to a virtual format during the pandemic.)

“Are you going to dress someone up like an animal again?” asked an eager fifth grader at Drummond Elementary this week. I’d called on the student with his hand up because I was hoping that he’d answer the question I had just asked: “What do you remember learning on my first two visits to your classroom this year?” 

Jane Weber, our MuseumMobile Educator, recently developed three new lessons for our fifth grade classroom visits. In the fall, students learned about white-tailed deer, and practiced deciphering a deer’s age by the teeth in cleaned jawbones. For our winter visit, we dressed two students up like fish, and compared the adaptations of prey fish (sharp spines, laterally compressed bodies, and eyes on the sides of their heads) with predator fish (sharp teeth, torpedo shaped bodies, and eyes on the front of their head). 

Now, for our spring lesson, we were about to learn about beavers. Like all animals, beavers have an impressive suite of adaptations that help them survive in their habitat. As teachers, Jane and I have adapted to a 5th grader’s sense of humor, and designed the lesson around dressing a kid up like a beaver.

I started with the feet. Beavers’ hind feet are webbed, of course, to help propel them through the water. Oddly, they also have a split nail on their second toe, which acts like a comb for spreading oil throughout their fur and removing debris. That oil is very important to beavers as they swim underneath the ice all winter long. Without it, they would be wet and chilled to the bone. So, after fastening two giant foam webbed feet around my victim…er volunteer’s ankles, I also handed her a photo of an oil can.

Two brown gloves went on next. Beavers have surprisingly dexterous hands that they use to bring mud to their dam and lodge, to hold twigs while eating, and to dig out deeper channels for swimming. 

The class roared with laughter when I pulled a fancy faux fur jacket out of my tub. These students have been growing up in our MuseumMobile program since they were in pre-K, and some of them remembered feeling the soft pelt of a beaver in their early years. One girl gazed off into the distance as she described the soft, warm underfur of her memory. Another piped right in to tell me about beavers’ longer, shinier guard hairs that help shed water. 

Jane had sneakily sewn a strip of Velcro under the back hem of the jacket. To this, I affixed a giant, flat, brown beaver tail, which also got a laugh. I also pulled a real (dried) beaver tail out of my tub to show around the class. They’d also seen this in kindergarten, but beaver tails never get old. Of course one kid peered at the cut end and exclaimed in disgust. Beavers use their tails for fat storage, and the now desiccated fat isn’t exactly pretty. But it was useful when the beaver was alive. That fat fuels their metabolism during the long winter to help them stay warm. 

The students easily came up with three more uses for a beaver’s tail: swimming rudder, warning signal, and a kick-stand to help them balance when cutting down trees. Their tails also help beavers dive quickly under the surface, and help them stay cool in the summer. One thing that a beaver tail isn’t useful for: patting mud onto their dam and lodge. Only cartoon beavers do that. 

Before handing our beaver her Mardi Gras-style mask on a stick, I brought out a real beaver skull. This isn’t the first time these students have seen that exact skull. It’s neat to provide continuity through the years. In kindergarten they have their first introduction to beavers, admire the skull, and feel the stick that’s been de-barked by a beaver’s teeth. In second grade we bring out the beaver skull to illustrate how the teeth of an herbivore differ from that of a carnivore. In fourth grade, when we dissect owl pellets and find lots of little mouse skulls, I show the beaver skull as a bigger example of a rodent’s orange front teeth. 

Today we look more closely at the skull, and talk about the iron that stains the teeth orange, giving them added strength. We also note that the eyes, ears, and nose of a beaver are all sitting right at the top of its head. Even while swimming with their body completely submerged, beavers can have all of their senses attuned to danger. 

Before I hand our volunteer her mask, I ask the kids how many of them use goggles for swimming. Beavers have built in googles, I tell them, and of course we’re all jealous. I’ve never met a pair of goggles I like. But beavers have a third, clear eyelid, called a nictitating membrane. It protects their eyes from debris while they swim. I show the class a clear plastic lens covering the eyes of our beaver mask, then hand it over to our busy beaver. 

The last prop is a pair of ear muffs. Water in your eyes isn’t the only issue. Beavers have valves in both their ears and nostrils to keep the water out while diving. Now we’re all seriously jealous, as we commiserate over how terrible it feels to get water up your nose or stuck in your ears while swimming. Beavers may look a little odd, but they have some sweet tricks up their fur. 

Our completed beaver now spins slowly to show off her adaptations, and we applaud her cooperation before dismantling the costume. 

Then I pass out bingo cards filled with pictures of animals. The dams that beavers build, and the ponds that fill in behind them, are incredibly valuable habitat for countless species. I start calling off animals that rely on beavers: songbirds, wood ducks, kingfishers, mink, dragonflies, great blue herons, deer, pileated woodpeckers, and water lilies. At this point, the entire class is on their edge of their seats, just needing one more square to win. Of course, I’m chuckling to myself, because I designed three different bingo cards that would all win at the same time. “Leopard frog!” I call, and the class erupts. 

As I clean up my supplies and wrap up the class, I’m still chuckling to myself. “Bingo!” I think to myself. Jane did a great job designing a lesson to teach fifth graders about the amazing adaptations of beavers. 

(Check out the virtual version of this lesson I created last spring! )

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.

Thursday, August 27, 2020

Rare Plants in a Rare Place

An old two-track led us into the woods, but almost immediately we veered left and crashed off into the unknown. Bushwhacking means alternating between watching your feet on the uneven ground, and protecting your eyes as twigs swing back or appear out of nowhere, so when I finally looked up, I was stunned. A bedrock cliff rose straight out of the creek bed we’d just crossed. Where were we? 

The craggy rocks, deep hemlock shade, and lush understory of ferns felt more like my botany field trips in the mountains of Maine, New Hampshire, and Vermont, than plain old Wisconsin. As I admired exposed faces of pink granite, it dawned on me that these rocks are part of a mountain range—albeit a very old and worn-down one. The low hills of Penokee Range stick up higher than most other things in Northern Wisconsin, (but lower than the younger mountains out east,) and also contain some of the highest quality plant communities in our area.

“Here it is,” came Steve Spickerman’s voice from up ahead. Spickerman is the Forest Ecologist for the Great Divide District of the Chequamegon-Nicolet National Forest (CNNF), and part of his job is keeping track of how rare plants are doing. I picked my way over moss-covered rocks toward Steve, and found a familiar-looking fern nestled in among boulders near his feet. It wasn’t familiar because I’ve seen it recently, but because I used to see it all the time in Maine and Vermont while I was in graduate school at the University of Vermont.

Braun’s Holly Fern has evergreen leaves and likes dark, damp habitats. 
Photo by Emily Stone.

While common out east, Braun's holly fern (Polystichum braunii), is a Wisconsin Threatened plant. Its evergreen leaves were shiny and robust, and near the ground the stalks were fringed with big, papery scales in an orangey shade of tan. This fern needs the cool, shady habitat often found on rocky, forested slopes; in ravine bottoms; and at the bases of cliffs. Check, check, and check. Wisconsin’s climate is likely a little on the dry side for holly fern, which may be why it is uncommon here. 

Around the world, this same species is native to Alaska, British Colombia, Newfoundland, Europe, China, and Japan. Braun’s holly fern also occurs within sight of the popular hiking trail at the nearby St. Peter’s Dome recreation area, but hardly anyone pauses long enough to notice. I, for one, am typically focused on spring wildflowers instead of the green backdrop of ferns. 

As we meandered farther down the ravine, the angular rocks went from being the size of basketballs and wagons, to being the size of refrigerators and sofas, sometimes with slopes of smaller talus intermixed. On one of those jumbled slopes, Steve stopped again. This time, the fern at his feet wasn’t robust and evergreen, it was flimsy looking and yellow around the edges. Its fronds were also a little shorter and wider than the typical fern geometry. The leaves will soon wilt into the ground for the winter, and begin from scratch next spring. 

Spreading wood fern (Dryopteris expansa) is another cosmopolitan species. It was first described in Germany, and also grows in Spain, Greece, eastern Asia, and California. According to the Wisconsin DNR, the habitat of this “Special Concern” plant is, “cool coniferous (balsam-fir, white cedar, hemlock) to mixed forests, sometimes in cold canyons.”

Spreading wood fern is a species of “Special Concern” in Wisconsin. Photo by Emily Stone.

Finding these two ferns—with their surrounding rock fields showing few signs of disturbance—was pretty much all that was needed for the official rare plant survey that was our goal for the day. With some species, like the highly rare and coveted ginseng, the botanists will actually count and mark individual plants so they know for sure when one is gone (vs. just being hard to find). These ferns only require a general check-up every few years. 

“I have the best job on the Forest,” Steve told me as we admired the unique landscape. His field tech, Stephen White, who just earned a permanent position, nodded along in agreement. These guys are a testament to the fact that the Forest Service isn’t just about cutting trees. They also manage landscapes for plants who could never become lumber, and for wildlife who no one hunts. In order to manage well, they do lots of scientific research and monitoring, too. 

Steve Spickerman, Forest Ecologist for the Great Divide District of the Chequamegon-Nicolet National Forest, points out more rare ferns on rocky cliff. Photo by Emily Stone.

Even with rare ferns all around my feet, I couldn’t stop looking up. Sheer cliffs, talus slopes, twisted trees growing out of giant boulder fields…it really didn’t feel like Wisconsin. With such a locally rare habitat type, it’s no surprise that this area—the untracked forest beyond tourist-packed Morgan Falls—has one of the highest concentrations of rare plants on the entire Chequamegon-Nicolet National Forest. 

The specialness of this area has been on many peoples’ radar for decades. The area around St. Peter’s Dome was recommended for inclusion in the Eastern Wilderness Areas Act of 1975, but a snowmobile trail through the center of it was just too popular. Instead, it’s been designated as a Special Management Area, a Research Natural Area, a State Natural Area, and an Important Bird Area.

As I scribbled notes about the day in my little field notebook, Steve chimed in. “Please make sure people know that this area is out here for them to enjoy…but there are rare plants, rare snails, and fragile habitats everywhere, so they should be careful to stay on the trail.” That’s good advice for many reasons, including the chance that you might get lost in a place that looks nothing like Wisconsin.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.

Thursday, August 20, 2020

Ospreys Right on Schedule

The setting sun was in my eyes and a headwind in my face as I rounded one of the many curves on County Highway D along the eastern shore of Lake Namakagon. Eager to see today’s news, I squinted through the trees as I coasted along, and watched for that first glimpse of the nest. Who would be home today?

Visible by boat, car, and beer-and-pizza deck, the osprey nest near the Loon Saloon on Lake Namakagon is a staple of local wildlife watching. This year, my usual schedule disrupted, I’ve made the nest a destination on more bike rides than ever before, and was rewarded with many great osprey observations. 

As soon as cold winds first licked at patches of open water last spring, I was out searching for returning migrants. In my Runkeeper app, I labeled my bike rides with who I observed. April 1: no osprey. April 10: loons, but no osprey. April 15: one osprey on the nest. April 16: Two ospreys on the nest!

Male and female ospreys return back to the same nesting territory year after year. Within a pair, you can usually tell identify the female by the darker brown streaking on her chest. Photo by Emily Stone.

What a shock it must be for these world travelers to leave their wintering ground in Florida or South America and arrive “home” to the Northwoods with ice in the bays, snow squalls blustering, and ice storms threatening. As with many birds, the male arrives on the territory first, and the female joins him soon after. Ospreys are pretty devoted to their mate and their territory. It saves them a lot of trouble to simply head for home and know that your compatible partner will show up there, too. 

Through the end of June, my observations were pretty ambiguous. What did it mean to see one, two or no osprey on the nest? Were the missing ospreys off hunting? Was one hunkered down below the sides of the artificial nesting platform perched on top of a tall pole? 

Once I caught sight of an osprey carrying a stick. This was probably the male, since he brings sticks as a part of his courtship ritual, and the female will arrange them to her liking. Nest building sometimes continues through incubation and early chick-hood, so I couldn’t be sure what it meant about their schedule. After the pair copulates, it takes 14 days for the female to lay her first egg. She’ll lay another egg every one to three days, ending up with between 1 to 4. That’s weeks of action that I couldn’t see from the ground. 

Males occasionally take a turn at incubating during the day, but females cover the nest all of the 37 nights it will take them to hatch. She starts incubating as soon as the first egg is laid, and the chicks hatch in the order they were laid. Those third or fourth chicks are often much smaller, and are the most likely not to survive. 

Finally, on June 23, I hit the jackpot. One adult osprey perched on the edge of the nest, and two small heads poked up above the wooden rim. In the dim evening light I couldn’t see many details, but two days later I again saw a juvenile’s head in better light. Already past the downy stage, the little one was sporting small, sleek feathers with the distinctive black eye stripe of their parents already visible. Both ospreys’ eyes glowed in the sunlight—the chick’s were dark red (a juvenile trait) and the adult’s were yellow. I later heard reports that there might have been three—or even four—chicks in the nest at some point, but I never saw more than those two. 

The young osprey chicks’ heads only barely stick up above the sides of the nesting platform. More than 80% of occupied osprey nests in Wisconsin are found on man-made structures. Photo by Emily Stone.

Osprey chicks must grow fast. Newly hatched, they weigh only 1.8-2.1 ounces. By the time they fledge in 8 to 10 weeks, they’ll weigh between 32 and 64 ounces (that’s 2 to 4 pounds)! A diet of fish fuels that growth. To hunt, an osprey will hover above the water, peering into the shallows with sharp-eyed concentration. Although a dive may begin head-first, it ends with talons outstretched as they plunge into the water. Special scales and sharp barbs on their toes help them grip on to slippery fish. A reversible outer toe allows an osprey to carry a fish with its head facing forward, in the most aerodynamic position. With strong wings, they can carry fish up to about a foot long and about 4 pounds. 

The next time I spotted the chicks, they were clearly adult-sized teenagers. Buff tips on their dark feathers, dark streaking on their pale tummies, and red eyes gave away their age. Oh, and their behavior. One chick flapped awkwardly, ejected a mute (poop) over the side of the nest, and then hunkered down by Mom as if for a nap. 

Now too big and restless to hide down inside the nest, the juveniles showed up more regularly. On one long bike ride, I found an empty nest and a single osprey was hovering on the wind, swooping and doing acrobatics over the lake. When this aeronaut landed, their mottled juvenile feathers became visible. The youngsters were flying! An hour later, as I headed back past the nest, both chicks were at home. One of them was tearing fiercely at a large fish. A first catch perhaps? I didn’t expect them to grow up so fast!

Of course, migration is about to begin again, and virtually no ospreys will be left in Wisconsin by the end of October. The young ospreys will migrate alone, relying on instinct instead of parents to show them the way. And then they’ll stay there—in their warm wintering grounds—for two or three years before they return north to breed. 

I’m not quite ready to see them go. So, watching eagerly for that first glimpse of the nest as I biked along, I held my breath. A single osprey perched on the wooden nest platform. Zooming in for a photo, I quickly confirmed they were one of the red-eyed juveniles. It’s eight weeks after my first glimpse of their little heads. My schedule may have been disrupted this year, but the ospreys are right on track with theirs!

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.

Thursday, August 13, 2020

Signs of Fall

At the end of one of those perfect summer days—sunny and 75, with low humidity—I hopped on my bike for scenic ride along the east side of Lake Namakagon. A light breeze tickled the water, and brought to my nose the sweet smell of algae being tossed and turned at the surface. I scanned for otters among the thick beds of water lilies and purple-blooming thickets of pickerel weed. And then a glimpse of color caught me by surprise. I don’t remember what came out of my mouth. It was some garbled shout of startled dismay. There, in the corner of the bay, where the forest and marsh grass intermingled, stood a maple tree with every single leaf changed to red. 

This isn't the red maple I'm writing about (that photo taken from a moving bike didn't turn out) but it's another great example of a swamp maple turning early. 

I love fall. This year, though, I’m not ready for summer to be over. The Museum only just opened to the public, after pandemic-related delays in the construction of our “Mysteries of the Night” exhibit. My usual milestones of Loon Pontoon Tours, Master Naturalist Programs, our Summer Benefit Party, and Junior Naturalists playing games in the Outdoor Classroom were nowhere to be found. And now, already, by the first of August, signs of a changing season have appeared out of nowhere. 

Honestly, red maples catch me off guard every year. These adaptable trees can survive in both wetter and drier soils than their sugar maple cousins, but not without sacrifices. The soil in swamps is often low in essential nutrients. Unlike trees in richer soils, “swamp maples” can’t risk losing any nutrients to an early frost. Each year around the beginning of August, they pull valuable nitrogen and phosphorus back out of the leaves and into the twigs, where they’ll remain on-deck to fuel next spring’s leaf growth. 

Next, sugars in the leaves break down and form anthocyanins. Anthocyanins are pigments that absorb UV light, especially at low temperatures. Like sunscreen, they protect the leaf cells. They provide cover while swamp maples withdraw every last nutrient drop from fragile leaves. To create anthocyanins they need lots of sugars, which requires dependable soil moisture and sunshine. Happily, that’s the definition of a swamp.  

That red maple opened my eyes to other signs of fall I’d been trying to ignore. The dappled yellows in the roadsides show that the oval leaves of spreading dogbane and the lacey fronds of bracken ferns are following red maple’s example. While their yellows will soon drift to the ground, another one flashes upward. Yellow-shafted northern flickers are one of our only migratory woodpeckers, and right now they’re heading from Canada to the southern U.S. 

While on the ground, flickers’ smooth brown back with black bars and dots blends in well with soil and leaf litter. They catch ants and other insects with their long, sticky tongues. As they startle, handsome yellow feathers are visible under their wings and tails, and yellow feather shafts show through from above and below. Their white rump patches flash brightly and give another vibrant identification clue during short, undulating flights.

Once flickers lead your eyes to the edge of the woods, mushrooms start to materialize in the shadows, too. Along my driveway, the pure white blobs of Peppery Milkcaps have emerged from the netherworlds, still wearing little caps of pine needles and oak leaf duff. I’m always amazed by the way that mushrooms seem to appear out of nowhere after late summer rains. The Anishinaabe noticed this, too, and use the word “puhpowee,” to describe “the force which causes mushrooms to push up from the earth overnight.”

Peppery milkcap mushrooms aren’t edible, but that’s ok because my gardens are thriving. As I poked around the hops vines and ferns—still in my bike shorts and vest—I found several small, orange dragonflies perched in the waning sunshine. Once I’d identified them as female autumn meadowhawks, using the SEEK app, it became easy to discover that these are the one of the latest dragonflies to emerge from their aquatic childhoods each summer. The adults are unusually tolerant of cold, and withstand temperatures of 50 degrees F or lower as they survive into October and November. 

Also in my garden, I spotted a very fat monarch butterfly caterpillar. Will this one become a butterfly that flies to Mexico, or a monarch who lays more eggs and sends her progeny south for the winter instead? It’s around this time of year when the day length, temperature fluctuations, and worn-out milkweed plants trigger caterpillars to metamorphose into the “super generation” of butterflies. They will live eight times longer and travel ten times farther than their parents and grandparents. 

They’d better move fast. Already, our pollinator gardens have reached their peak, and some blossoms are beginning to fade. Out in the roadsides, the bright pink flowers of fireweed have bloomed their way up the stems with seed pods chasing close behind. A few have even burst open to reveal clouds of delicate fluff. “When fireweed turns to cotton, summer is soon forgotten,” they say in Alaska.

It’s a nice rhyme, but it’s not quite true, is it? These perfect summer days—with their colorful hints that fall is coming—are when we kick our memory-making into high gear. Every swamp maple we see dressed in its autumn attire is a reminder to enjoy the end of summer to its fullest and store up memories of sunshine for the long winter ahead. 

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.

Thursday, August 6, 2020

Butterflies are Weird

On one of those steamy, hot, and humid mornings last month I found myself staring out of my air conditioned office at the Museum’s vibrantly blooming pollinator gardens. Movement caught my eye, and I wandered outside with my camera and tripod to catch some of the action. By the end of the day, I had realized that butterflies are not only lovely, but really, really weird. 

As I’d hoped, a lovely orange butterfly was sipping eagerly from the pale purple bergamot flowers. Zooming in, I could watch as she probed the cluster of tubular flowers with her delicate proboscis. Except, calling it sipping isn’t quite accurate. 

A butterfly’s proboscis is more like a paper towel than a drinking straw. Like a paper towel absorbs water when even a corner touches the puddle of spilled milk, tiny grooves on the inside of the proboscis pull liquids upward using capillary action. The inner structure of the proboscis also breaks the column of liquid into tiny droplets that pose less resistance. 

Trying to suck the liquid up would require more force than the butterfly can exert, especially since butterflies don’t just drink thin nectar, they also consume water from puddles, juice from rotten fruits, animal tears, tree sap, and several other unexpected substances of widely varying thickness. As you might expect, different butterfly species have fine-tuned their proboscises to match their preferred food—even dried food.

Earlier this June, on a trip to Moquah Barrens, I snapped some photos of a dense mass of silvery checkerspot butterflies crowding around a lump in the sandy wheel track. What were they eating? A closer look revealed that the lump was a hairy, old wolf scat. Your first reaction to this might be a revolted “why?” Your next question might be “how?” Let’s tackle the “how” first. 

It’s actually pretty simple. Butterflies can send watery saliva down through their proboscis and onto the dry surface, where it picks up the substances they desire, and then travels back up the tube’s tiny grooves. Remember when we used to make Kool-Aid by adding water to powder? 

The “why” is a little weirder. Butterflies are drawn to the scat (poop) of carnivores, but also to mud puddles, rotting plants, and dead animals. Those gross things are a source of the nitrogen and sodium that are lacking in the butterflies’ usual diet of flower nectar. In most species, only males will “puddle.” He then passes these valuable nutrients on to a female when they mate so that she can use them to produce healthy eggs. It’s called a “nuptial gift.” I mean, who wouldn’t want a little packet of the essence wolf scat or mud puddle on their wedding day? Seriously, those are two of my favorite things!

Speaking of butterfly mating practices (I did mention that the day was hot and steamy?), the Museum staff got a good laugh last week when one of our volunteers walked across town just so she could impress us with the fact that “butterflies have eyes on their genitals!” That sent me down a Google black hole!

Well, technically they are simply photoreceptors that can detect ultraviolet light, not eyes that can see movement and shapes, but it’s still an impressive discovery (by accident) into the sensory world of butterflies. This research was done on the Japanese yellow swallowtail butterfly in 2001, but extraocular photoreceptors—light-sensitive structures that are found outside of an eye—occur in many animals. 

What’s the use of literally having “hindsight”? It’s different for males and females. They both have two small patches of photoreceptors covered by transparent cuticle. In male butterflies, the patches are located so that when he has successfully connected with the female during mating, the photoreceptors go dark. Once he knows his aim is true, he can deposit both sperm and a nutritious nuptial gift that also acts as a plug. 

In females, the photoreceptors aid in egg laying. The whole process takes at least three types of sensory organs! First, a female butterfly will use chemical receptors on her front legs to taste a plant and make sure it’s the right species for her caterpillars. Then she extends her ovipositor, and uses the two photoreceptors to tell her that it isn’t obstructed by a bit of schmutz, which would block light, and also eggs. Finally, as she pushes her ovipositor against the leaf, pressure sensors tell her that a leaf is really there, and she deposits an egg. 

The full story of the discovery of the photoreceptors is pretty fascinating, and I recommend reading the full article, “Hindsight of Butterflies: The Papilio butterfly has light sensitivity in the genitalia, which appears to be crucial for reproductive behavior,” by Kentaro Arikawa of Japan. 

The monarch who was (not sipping) on the bergamot flower fluttered away. I’ve always admired butterflies for their beauty and pollination services—but in hindsight—the weirdly elegant solutions they’ve found to life’s various problems are even more amazing.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is now available to purchase at Or order it from our friends at to receive free shipping!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. The Museum is now open with our brand-new Mysteries of the Night exhibit. Connect with us on Facebook, Instagram, YouTube, and to see what we are up to.