Why Woodpeckers Don’t Get Concussions

Years ago, Lois Nestel, the Museum’s founding director, wrote:

“I was stalking a pileated woodpecker whose calls and rapid fire hammerings seemed to come consistently from one area of trees not far from the house. These big, wary birds are not easy to pursue, so reasonable caution was necessary.

“Silence ahead seemed to indicate that the big bird had flown, but the apprehension was dispelled as, from a pine stub ahead, there came a staccato burst and bits of flying wood. A stealthy approach, timed with the pecking, ended abruptly when a large black beak topped by bright eyes and a flame red cockade was suddenly thrust around the side of the stub. With much scuffling of feet the crow-sized black body came into view. Unaware of being watched, the big bird seemed to talk to himself with soft knocking notes as if trying to decide where to drill the next hole.

Pileated woodpeckers have been increasing in numbers as we allow trees to get big and old. Photo by Emily Stone.

“Some unwary movement or sound on my part suddenly alerted him. There was a brief eye-to-eye confrontation; then the broad wings spread and with a few swooping beats bore the great woodpecker into the safety and seclusion of the forest.

“The pine stub bore evidence of much work. Large openings had been chopped through the shell and into the honeycombed interior. Breaking open a piece of this riddled wood revealed the dormant bodies of large black ants. This was what had attracted the woodpecker and would undoubtedly bring him back again. I might not be around to see, but the sound of drumming would bring to mind a clear picture of a great black bird with a flaming topknot—a memory to treasure.”

Lois’s experience with the woodpecker in the forest is timeless. How many of us have had the thrill of seeing or hearing these large birds swoop across the road, tear apart a backyard stump, or disappear into the forest? Actually, far more of us than in Lois’s day. Unlike many birds, populations of pileated woodpeckers have been increasing since 1966 due to the regrowth of large trees and the conversion of some large trees into food-rich snags. I’m sure Lois would be thrilled!

These days, during my own frequent encounters with pileated woodpeckers, I can think about the science behind the question I asked in the first chapter of my second book: “How can that little bird bang his head against trees all day and not develop debilitating headaches?”

Some of the initial research into this question, starting in the 1970s, proposed that areas of sponge-like bones in a woodpecker’s skull act as shock absorbers to protect the brain. Subsequent research, and logic, has disproved that. Pounding with a squishy hammer means that you have to pound harder to get the work done! Instead, newer research shows that a woodpecker’s muscles engage in a way that stiffens their body and transfers energy more efficiently. This seems to include exhaling with every bill strike—just the way I grunt to stabilize my core while picking up something heavy.

This female hairy woodpecker can pound away all day and not get a concussion. Several simple adaptations make that possible. Photo by Emily Stone.

When I wrote about pileated woodpeckers in February 2022, I was excited that some scientists had celebrated the woodpecker’s tongue as a brain-protector. Woodpeckers have a long tongue that wraps around the back of their skull. A Y-shaped bone called a hyoid apparatus supports the tongue and helps it extend into tree holes and extract insects for lunch. The researchers hypothesized that it also acts like a seatbelt for the brain. This was a fun “fact” to share with people!

After a neighbor suggested recently that I write about pileated woodpeckers again, I decided to see if there was any new research. Indeed! In 2024, James M. Smoliga of Tufts University School of Medicine summarized and critiqued the research on woodpecker brain protection. He criticized the hyoid seatbelt hypothesis for making conclusions based on preserved tissues with altered characteristics and the biomechanical properties of a human tendon. I will have to stop telling people that a woodpecker’s tongue cushions their brain.

Downy woodpecker with a sharp, stiff beak.  Photo by Emily Stone.

Smoliga concluded that, as far as current research shows, woodpeckers survive banging their heads against trees because they have less fluid in their brains than we do, which limits the “sloshing” of their brains within their skulls. And, in contrast to the impacts that cause concussions in humans or concussion-like symptoms in birds who have hit windows, woodpecker’s strikes are short, intentional, and involve coordinated muscle movement from back to front in a linear vs rotational way. The newest calculations, made with the most accurate modern technology, predict that a woodpecker would have to strike a tree twice as hard as usual to give themself a concussion.

Of course, any of these conclusions might be proven wrong or incomplete as scientists discover new information in the future. The beauty of science is that it requires us to be able to change our minds in light of new evidence. One thing that doesn’t need to change is the magic we feel, as Lois did, when we watch a great black bird with a flaming topknot spread their broad wings and with a few swooping beats disappear into the forest.

Emily’s brand-new 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.

Cute Bits of Camouflage

The wide brown trunk of an ash tree in front of my house makes a good backdrop for assessing the density of falling snowflakes, their potential impact on the ski trails, and the unique beauty of a particular storm. While gazing at it last week, a bit of the bark began to move. The optical illusion lasted only a second before I recognized the small oval of brown-and-white patterning as a bird.

Brown creepers are cute little bits of camouflage with white bellies. This one moved upward in staccato motions, a bit to the side, around to the back, back to the front, and up some more. Pausing, the bird used their thin, downward-curving bill to explore a bark furrow. Perhaps they had spotted an overwintering insect larvae or antifreeze-protected spider for their lunch. Near the limit of my view out the window, the creeper suddenly launched off the tree and fluttered downward toward another tree trunk, out of sight.

Chickadees taking turns grabbing sunflower seeds at my feeder distracted me for a second, until movement at the base of the same tree again caught my eye. The brown creeper (or their mate?) was spiraling upward again. Apparently, there are enough crevices in a big tree like this that it pays to make many trips around the trunk.

Can you see the long claws and curved beak on this brown creeper? Photo by Emily Stone. 

The creeper hopped with both feet at once, and I knew that their curved claws were gripping tight. Their long, stiff tail braced against the bark. Just above a knothole, the creeper paused again and probed excitedly in a crevice until a flurry of motion brought a red-breasted nuthatch to that spot and the creeper flew off. The nuthatch circled, probing in the bark with their long, straight beak. Thief!

Having cleaned out that crevice, the nuthatch continued foraging downward on the trunk. Nuthatches are also known for their agility in navigating tree trunks, but whereas creepers go up, nuthatches specialize in going down. They are assisted by one backward pointing toe with a long claw on each foot. Nuthatches can hop in every direction, though, and even dangle on the twig tips with acrobatic chickadees. Their very short tail stays out of the way.

Nuthatches are known for climbing head-down, but are pretty versatile. Photo by Emily Stone. 

The first lesson in my first ornithology class back in college used these two birds as an example of how to identify a species by their behavior. Brown creepers hop up a tree, then fly down to the next one. Nuthatches walk down and then fly back up.

Classic nuthatch behavior! Photo by Emily Stone. 

Although both nuthatch and creeper populations are thought to be stable, I see and hear many more nuthatches while I’m out in the woods. This is partly due to their brighter colors and louder calls. Nuthatches shout their distinctive yank! yank! yank! pretty consistently as they feed in mixed flocks with chickadees and woodpeckers. Brown creepers, on the other hand, have thin, high voices that are easily lost among the contact calls of other birds. I’m not the only one who tunes out their songs. A study published in The Canadian Field-Naturalist journal in 2020, discovered that brown creepers do sing in the dawn chorus, but it took an automated recording to notice them consistently.

It's not just that nuthatches are easier to see and hear. They are also far more numerous. There are almost three times as many red- and white-breasted nuthatches in the world as brown creepers! Perhaps this is because brown creepers have some unique habitat requirements.

Brown creepers need forests with large trees for both foraging and nesting. They build their nests behind pieces of loose bark, which are more common on large trees that are dead or dying. Big trees also have deeper furrows for hiding the tasty insects and spiders that creepers prefer. Creepers occasionally eat seeds or suet, but rarely visit feeders. One study found that the gnarly bark of large yellow birch trees make good habitat in the East, while they are found in conifer forests in the West. These populations of creepers may actually be different subspecies, but physically they blend in with each other as much as they do the trees. It’s only through DNA studies that scientists are learning to separate them.

Nuthatches seem to thrive in a wider range of habitats and ages of forests. Nuthatches reuse old woodpecker cavities for nests, and sometimes excavate a hole themselves, but these can be in smallish trees. Both red-breasted and white-breasted nuthatches are much more likely to eat seeds than creepers, which expands their options to include bird feeders.

Happily, the greedy nuthatch didn’t scare away the brown creeper for long. As the snowflakes drifted down, the cute little bit of camouflage returned to the tree for another expedition up, lifting my spirits as they went.

Emily’s brand-new 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.

Mulling over Mullein

This is the season for lists highlighting our most-listened-to or best-of-whatevers at the end of the year, so I decided to dig into the stats on my Natural Connections blog. To my surprise, the most-read article in 2025 was one I wrote in February of 2016 about a plant called mullein. In August 2025 it spiked in popularity, far above my normal readership. I have no idea why. I recently told someone the story of finding the chickadee-cached seed in the mullein stalk, but I’d forgotten about the rest of the article. It’s fun! And appropriate to this season. So, I hope you enjoy it as much as the 1.24K other readers did, too! Happy New Year! –Emily

Something in the quality of the pre-dawn light told me that the world had been made new with a fresh blanket of snow. I love waking up to a clean slate. What furry or feathered stories will lay their tracks on it today? Artists, with their warmer, drier canvases, must have the same feelings of anticipation and eagerness to see a new creation emerge. As a child, I felt that way on the first day of school, too, with my stack of blank notebooks, ready for a new adventure.

Even as the Sun rose, there was already one mark in the snowy expanse of my front “yard.” Sticking out of the snow like a proud sentinel was the dried stalk from a common mullein plant. I’ve been watching it since last summer, when its yellow-flowered stem was just a dab of color among daylilies, black-eyed Susans, and daisies. Today it was the center of attention while all of its companions lay resting under the weight of the drifts.

Although this mullein stalk is far more dead than its dormant neighbors, the sturdy, dry stem gives it a second life. This plant began during the summer before last, when a tiny seed found enough sunlight and bare soil to sprout. Mullein likes disturbed areas. Soon, a low circle of leaves, called a basal rosette, spread out on the earth. This biennial overwintered that way, with its leaves and roots hidden beneath the snow. A period of cold and dormancy is required to break down starch in the roots and trigger its next life stage.

In the spring, a thick stalk began to grow out of the basal rosette’s center. Once the spire was chest-high, the lowest flowers, starting about half-way up the stalk, began to blossom in clusters. Small and yellow, with five symmetrical petals, each flower only bloomed for a single day. It opened before dawn and closed in the afternoon. If a bee didn’t pollinate the flower during that short window, the flower did the job itself. With such measured restraint, a single stalk of mullein can bloom for an entire summer.

Over the summer, mullein flowers open in succession up a tall stalk. Photo by Emily Stone.

Once that summer is over, though, the mullein is done. Each plant only lives through two growing seasons, while the durable, dried stalk persists much longer.

Chickadees scattered from the bird feeder as I tromped outside to take a closer look at my sentinel in the snow. Up close, I could see tiny, roundish seed capsules split open down a center seam and clustered among the few dried flower petals still clinging to the top of the spike. Each of the hundreds of capsules can hold more than 700 seeds, each less than a millimeter long.

The flower stalk’s usefulness doesn’t end after it goes to seed, though. Mullein is a notoriously useful plant among survivalists and other wildcrafters. For one, it provides everything you need to start a fire. The lower portion of the stalk becomes a spindle for a hand drill or bow drill. The thick base of big stalks can be split and used for the fireboard that rests on the ground and holds the spindle and eventual ember. The tough root can be fashioned into a hand socket for pressing down on the top of the spindle when using a bow drill.

Once you get a hot coal, mullein leaves make excellent tinder. Held vertically on the stalk all winter, they are often dry when everything else is wet. Plus, their fuzzy texture provides ample surface area to ignite. Once you’ve coaxed a little flame, the uppermost club of seed capsules is useful as kindling. The fuzzy leaves are also a skin irritant and can either be rubbed on your cheeks for “Quaker rouge” or give you contact dermatitis. Beware of the wide basal leaves’ purported use as “cowboy toilet paper.”

The leaves of common mullein are covered in tiny hairs that protect them from grazing animals and bright sun. Photo by Emily Stone.

While mullein isn’t native here (Europe, northern Africa, and Asia are its home range), it has spread quickly since the 1700s, and is considered naturalized in most places. Native species as well as other newcomers find it useful, and it only threatens to take over where other plants are sparse.

As I stooped near the flower stalk for a photo, another use caught my eye. Hidden among the seed capsules was a single, hulled sunflower seed: the food cache of a chickadee. Leaning even closer, I bumped the stalk and sent a shower of tiny black seeds onto the snow. They are too small for the chickadees to bother with, but goldfinches have been known to eat them.

Can you spot the sunflower seed that a chickadee stashed in this dried stalk from a mullein plant? I still think about how fun it was to actually find one of the chickadee's cached seeds! Photo by Emily Stone.

Most of the seeds will likely settle into the soil when the snow melts. With characteristic restraint, the seeds can persist for up to a hundred years. They wait for just the right conditions to sprout a new basal rosette and begin again. Their requirements? Bare soil, full sun: a clean slate on which to begin something new.

Emily’s brand-new 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 Bohemian Bird

Dawn was disappointingly gray over Lake Superior. Having been given a rare chance to wake up with a lake view, I’d hoped for something a little more spectacular. But a touch of color warmed the far horizon, and if I looked closely enough, a bit of sea smoke danced across the rippled surface.

Then movement closer up caught my eye. In the bare tree just outside the window, a flock of birds bustled. Their main activities seemed to be stretching up to pluck a mountain ash berry from its stem and then fluttering to another part of the tree in search of the next fruit. Their behavior, plus their dapper crests and rakish black masks, immediately identified them as waxwings.

Cedar waxwings are quite common in the Northwoods year-round. They nest near rivers throughout the northern half of North America, and I often spot them flycatching out over the water as I paddle by. Winter finds them eating berries across this country and into Central America.

Cedar waxwings have the same jaunty crests and rakish black eye masks as Bohemian waxwings, but they also have a yellow belly and white under their tails. Adults at least three years old also have a bright red spot on each of their wings. Photo by Emily Stone.

But cedar waxwings have yellow bellies, white under their tails, and just a dab of red on their wingtips. These birds’ bellies matched the gray of the low clouds, and under their tails was an orange that reflected the fading sunrise. The red on their wingtips was set off by jaunty splashes of white and yellow, with the yellow also banded across the tips of their tails. There was no doubt that these were Bohemian waxwings!

Bohemian waxwings have jaunty crests, rakish black eye masks, orange under their tails, a yellow tip on their tails, and three colors of markings on their wings. They are winter visitors to the Northwoods. Photo by Emily Stone.

Bohemian waxwings are less common visitors to the Northwoods. They breed in northwest Canada and Alaska as well as across northern Scandinavia and Russia, overlapping with their cousins, the Japanese waxwings. In the winter, they spread south into the western U.S., southern Canada, and northern Europe and Asia. In fact, it may have been a Swiss physician who first bestowed upon these widespread birds the name Bohemian. He based their original scientific name on a folk belief that the birds originated from Czech lands also known as Bohemia. Today we know that this region is just a small part of their winter habitat.

Who knew that there are Japanese waxwings? Not me, until researching this article!
Photo by  sunjiao - www.inaturalist.orgphotos398986107, CC BY 4.0.

Eventually, the term Bohemian, through an association with the roving Roma people, also came to mean wanderers, vagabonds, and free-spirited people who pay little attention to society’s conventional norms and expectations. It is this meaning that seems best applied to these unusual birds.

Unlike most songbirds, waxwings are happy to live in close association with their kin throughout the year and don’t bother to defend a breeding territory around their nest. Many of the beautiful and complicated songs we hear birds belting out during the dawns of spring and summer are meant to claim a territory and ward off competitors, but waxwings have no need for this. They don’t have a true song, but use high-pitched calls to communicate with their flockmates.

Bohemian waxwings are particularly mobile. While many other birds can be observed at the same nest site year after year, Bohemians don’t usually return to the same area to breed. Instead, they follow the abundance of fruit in both summer and winter.

Bohemian waxwing eating a berry. Photo by Lisa Hupp USFWS - Public Domain. 

Fruits are full of sugar, but not many other nutrients, so waxwings may eat double their own weight in berries in a single day in order to get what they need. Their short, wide intestines have enzymes to help break down the sugar, their large liver converts the sugar to energy, and they poop frequently to expel the seeds. When eating fruits that have dehydrated over the winter, waxwings must drink water or eat snow to avoid becoming dehydrated themselves.

Bohemian waxwings are known for their ability to find a tree full of berries in the middle of nowhere, descend on it en masse, strip every edible fruit from the twigs, and then disappear to their next meal. That’s exactly what they did as I watched.

This flock of Bohemian waxwings quickly stripped the tree of all fruit. Photo by Emily Stone. 

Waxwings hopped from twig to twig, sizing up each red mountain ash berry before stretching or fluttering up to nab it. Often the bird would mash the berry a bit in their beak before swallowing it whole. During brief pauses in feeding, the birds seemed to clean their beaks on a twig by wiping them from side to side. Some of the flock gleaned more berries off the red-stained snow beneath the tree.

Mountain ash berries provide food for many bird throughout the fall and winter. 

Photo by Emily Stone.

A few members of the flock shifted next door to another mountain ash tree with a few berries left. But that tree was soon stripped of all fruits, too. Eventually I got distracted with my own breakfast, and by the time I looked out again, not a bird remained. Happily the clouds had departed, too, and my day continued on much brighter than it had begun.

Emily’s brand-new 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.

Wintertime Porcupine

It was an early morning at the Cable Natural History Museum as I loaded up the van with our MuseumMobile totes, gearing up for a full day teaching about animal adaptations in the schools. Every Being has a fascinating set of adaptations that help them to survive in their habitat, and it is one of my favorite topics to teach about.

Heading north on Highway 63, the beautiful scenery never fails to keep me entertained as I drive through the picturesque nature of the Northwoods. While my thoughts wandered, a large dark spot high in a distant tree caught my eye. At first, I thought it might be a squirrel drey–a large nest of twigs and leaves built high in a tree. But as I got closer, I realized that it was a porcupine! Once my excitement calmed down, curiosity began to take its place. I began to wonder why exactly this porcupine was high up in the tree on this late fall morning. The answer may lie within the feeding strategies of the North American porcupine.

Once the vegetation has begun to go dormant for the fall and winter, porcupines change how they forage for food. They shift from their spring and summer strategy of feeding on ground vegetation and leaves to heavily relying on trees and shrubs in the fall/winter, often spending large amounts of time in a single tree. They target the cambium and phloem layers, the living, growing area between the bark and the water-carrying sapwood, responsible for transporting sugars. This transition from a wide variety of foods available in the summer to nibbling trees in the winter is a drastic drop in nutritionally valuable food for porcupines.

A porcupine high up in an Aspen tree. Photo by Emily Stone. 

Porcupines, like many animals, eat a large amount of food in the summer to put on weight for the coming winter. On average, porcupines will begin winter with around 50% body fat–similar to a polar bear or seal. However, porcupines have thrown the typical winter survival strategies to the wind. They don’t hibernate to avoid poor food availability, spend time in burrows to conserve heat and energy, or cache food to not spend energy foraging. Instead, they hang out in treetops, exposed to the elements, as they spend energy feeding on food with the nutritional content of cardboard. But recent studies show they still manage to only lose an average of 35% body fat over the winter! This lack of fat loss shows they have adapted to survive on a poor diet in harsh winter conditions. But how?

Studies show that a porcupine's metabolic rate slows in the winter, lowering their energy intake requirements. These low energy requirements, partnered with a high tolerance for dietary imbalances, moving very little while foraging, and their large fat stores at the beginning of winter allows them to mitigate body mass loss and survive winter.

The porcupine's impressive adaptations don’t stop there. Once more nutritionally valuable food is available, they are able to immediately put those nutrients to work and gain weight back. This is not a typical ability of many herbivores. Even when good food becomes available, other herbivore species are unable to quickly change how their bodies are being regulated and processing food, making them incapable of properly using those nutrients, and unable to gain weight immediately. Once again, the porcupine is proving to be an extremely adaptable species.

One of the best known adaptations of porcupines are their quills. These walking pincushions sport roughly 30,000 quills–specialized, hollow hairs that cover the porcupine's body. Quills are a porcupine's main defense against predators, and are a particularly mean one. As if getting stabbed by pointed quills isn’t enough, each quill is equipped with microscopic, downward pointing barbs. Once embedded into flesh, the barbs catch on tissue like many tiny fishhooks, making removal viciously painful and dangerous if the quill breaks off inside the tissue. But the brutality of a porcupine's quills doesn’t end there. Those tiny barbs hook farther into flesh the more the victim moves, and body heat makes them expand–making them even more painful and difficult to remove the longer they are embedded.

Close up with a porcupine. Check out those quills! Photo by Emily Stone. 

Between their unusual adaptations to survive winter, and their intricately hazardous quills, porcupines are a natural wonder. I could be entertained for days by the complex adaptations they have developed to survive in their habitat. Much to my surprise, while driving back along Highway 63 after teaching all day, the porcupine I saw earlier that morning was still there. No doubt they were putting those winter adaptations to use as they foraged for twigs and bark high in the tree.

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 Subnivean Zone Returns

Lake Superior was astonishingly calm as we walked out to a rocky point in the last rays of the setting Sun. With no wind and temperatures well above normal for late November, my fiancé and I only needed light sweaters and jackets to stay warm. It was a truly lovely day to be outside.

Lake Superior on a calm November, day. Photo by Emily Stone.

Lake Superior on a calm November, day. Photo by Emily Stone.

“Grandfather Alden would have called this a ‘weather breeder,’” I told Kevin. He didn’t read The Boxcar Children books by Gertrude Chandler Warner, but they were a staple of my childhood. In this early reader series, four brave siblings solve quaint mysteries with the help of their wise grandpa. In Snowbound Mystery they spend a glorious, bluebird day hiking around a mountain cabin before a blizzard socks them in. Their Grandfather called the bluebird day a “weather breeder.”

On The Weather Channel’s website, I found this explanation to confirm Grandfather Alden’s usage: “According to a late 19th century definition, a weather breeder is a beautiful day of ‘unusual fineness’… However, such a day is usually followed by bad weather.” A 1996 article about weather adages in The New York Times explains that the only science behind that saying is the law of averages. Good weather doesn’t cause bad weather, but since the weather is always changing, your good weather will soon turn to bad. Checking my weather app, I was thrilled to see the amount of snow in the forecast going up yet again. This day was certainly the calm before the storm!

Cold rain splattered my windshield the next day as I headed back to the shores of a smaller lake in Northern Wisconsin. Before cozying up indoors, I wrapped my digital thermometer in plastic wrap and tucked it under the bright green frond of an evergreen wood fern in the yard. This has become an annual ritual. On the weather station screen indoors, I could see that the newly placed sensor matched the air temperature in the mid-30s.

Can you see the white corner of the temperature sensor hidden under the fern?
Photo by Emily Stone.

Overnight, the wind howled and rain turned to snow.

As winter’s first snowflakes drifted through the dark, some landed on top of dead plants, fallen leaves, twigs, and other detritus of the forest floor. In many places, snow never fully reached the ground. That was surely true for the protected hideaway of my thermometer. By dawn, it was buried under six inches and counting.

Despite falling temperatures, the relative warmth of the cold rain and the residual heat of summer were still radiating from the soil. At sunrise, when I checked the weather station, the air temp had dropped to 24 degrees Fahrenheit, but the sensor cozied up to the earth under a fresh blanket of snow read 33 degrees. After two winters of thin snow, the Subnivean Zone has returned!

All winter long I will monitor the air temperature and the temperature of a thermometer I recently buried in the Subnivean Zone under the snow. In it’s first day of existence this winter, the Subnivean Zone did not drop below 33 degrees! Photo by Emily Stone.

In this magical space, with a blanket of snow to trap the earth’s warmth and provide a solid break against the windchill, temperatures hover around freezing even as the world above drops below zero. Deeper snow provides even more insulation, and all manner of Beings—from mice to martens, bacteria, fungi, spiders, hibernating insects, frozen wood frogs, and more—rely on the moderated microclimate.

In 2022-23—the winter of record-breaking snow—deep drifts accumulated on still-thawed ground, and the temperature in my front yard’s subnivium didn’t drop below 32 degrees for the entire season. The last two winters haven’t been so lucky. With thin, icy snowpacks, plant roots and mosses felt the sting of dry, bitter cold, ruffed grouse couldn’t dive into a snow cave to spend the night, and small mammals had to face the choice of staying safe and warm in a burrow, or risking being eaten or dangerously chilled while they foraged for food. Wood frogs in the leaf litter suffered without snow to buffer them from energetically costly freeze-thaw cycles.

Happily, at least for this week, those Beings are safe from the challenges of a snowless winter. Those Beings include me. Cold weather without groomed ski trails makes me sad. This week, my social media feed is full of good news about trails opening.

A weather breeder might be a day of “unusual fineness”, but I personally wouldn’t call what came after it “bad weather.” For many Northwoods Beings (the ones who don’t have to drive on bad roads or clear downed trees) snow and The Subnivean Zone are truly something to be thankful for!

Fluffy snow is a wonderful insulator to help retain warmth from the earth. Fluffy snow is also great for skiing up a gravel road! Photo by Emily Stone.

Emily’s brand-new third book, Natural Connections3: A Web Endlessly Woven, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

https://www.cablemuseum.org/books/ 

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 Bright Red Warning of Barberry

“A long time ago, the owner of that cornfield asked if I would sell this little piece of relatively flat woods to him,” my dad told me while walking me through a section of my parents’ land in Northeast Iowa. “He talked about cutting the trees and growing more corn.” As I looked out through the furrowed trunks of white oak, hackberry, chinkapin oak, walnut, basswood, and sugar maple to the monoculture of the field beyond, I was glad Dad had said no.

We’d just scrambled down the steep slope of our North Ridge. Looking back uphill, blocky outcrops of limestone nosed through a thick layer of autumn leaves. As part of the Driftless Area, this land has been shaped by flowing water instead of ice. The Turkey River—a tributary of the mighty Mississippi—had carved this ridge in one of its meanders through its floodplain. From the top of the North Ridge, we’d been able to look almost straight down at the channel carving the other side, too.

My dad, Larry Stone, looks from our North Ridge down to the Turkey River in NE Iowa. Photo by Emily Stone.

We sat down on a fallen log for a moment. Dad adjusted the cloth “tick gaiters” treated with Permethrin that he always wears out hiking these days. Iowa has plenty of deer and deer ticks, and multiple encounters with Lyme disease have made him cautious. The gaiters work on the same idea as tucking your pants into your socks to keep ticks from crawling into hard-to-see places. The addition of Permethrin means that the ticks aren’t just detoured, they die.

The pause also gave Dad a chance to snap a few photos of the late afternoon sun streaming through the trees. As I followed his gaze, a low bush with pinkish leaves off in the distance caught the light in a way that nothing else in the forest did. Hmm.

Japanese barberry bushes keep their rosy, red fall colors for a long time and are easy to spot in the November woods. Photo by Emily Stone.

The closer we ambled to this bush, the more sure I became of their ID. Finally, a close look revealed a few bright red, football-shaped berries dangling from rosettes of small, pink leaves. My hunch was confirmed. This was a Japanese barberry.

The bright red berries of Japanese barberry are one of the reasons this plant was favored as a decorative addition to landscaping until they began escaping gardens and becoming a haven for deer ticks and Lyme disease. Photo by Emily Stone.

The arching stems, decorative berries, and warmly hued, persistent fall foliage of barberry, plus the complete lack of deer browse on their twigs, are why they were brought to the U.S. as an ornamental plant in 1875. That was fine, until in the 1980s they started to spread out and displace native plants. Now Japanese barberry is considered invasive in 17 states, including Wisconsin, Minnesota, and Iowa.

Barberry changes the soil characteristics beneath the shrub in ways that make it hard for other plants to grow there. Combine that with early spring leaf-out that shades out competitors, arching stems that root wherever they touch the ground, and drought resistance, and a forest can easily be taken over by an impenetrable thicket that not even deer will eat. A barberry thicket also provides a safe, fox-resistant haven for mice, and a shady, humid home for ticks. Deer ticks feed on mice, who are reservoirs for Lyme disease.

The arching stems of barberry root wherever they touch the ground. Photo by Emily Stone. 

 

One study in Connecticut found that in an area with no barberry, about 10 ticks per acre were infected with Lyme disease. In an area with extensive barberry, that number rose to 120 infected ticks per acre. That’s not a future my parents want on their land.

Dad pulled a roll of pink flagging tape from his pocket, and marked both the bush and several trees in the area. Early the next morning, he returned to the spot with clippers and herbicide. Cutting the stems and brushing on herbicide is one of the recommended control techniques. Our family doesn’t love using herbicides, but if they are applied responsibly, they can be more effective than mechanical removal alone.

On a few hilltops where my parents have restored prairies, they use fire to keep the native plants healthy and the invasive species out. Historically, low-intensity fires might have kept this woodland healthy, too. In the absence of widespread fire, some folks have found good success at removing barberry by blasting them with the focused fire of a propane torch.

I was happy that we’d found and taken care of this one barberry bush before it spread too far and impacted the diversity and tick population of this lovely forest. November is a good time to get outside and spot the the bright red warning of barberry when everything else is gray. On the way back to the house the only other flash of red I spotted was a cardinal heading toward the bird feeders. That’s a bit of color I’m excited to see.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too. Natural Connections 3 is available for pre-order from Honest Dog Books!

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our Fall 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.