Grouse House

Two perfect tracks paralleled a sinuous curve of the frozen Montreal River. Back at the ABR ski trails near Ironwood, MI, I was enjoying a leisurely classic ski while my friends all zipped around the wider trails on their skate skis. The morning was perfect: blue skies, bright sun, and temperatures rising quickly out of the teens.

Here and there, a few animal tracks stitched their way across the trail. They were coyote, maybe, or red fox. Then a bigger depression beside the trail caught my eye. Was that a sitzmark from a clumsy skier? Not quite. Like an upside down exclamation point, a yard-long, foot-wide trough ended at a small bridge of unbroken snow. Capping it off was a chicken-sized snow angel.

Naturally, I slid to a halt and gingerly backed up in the tracks to get a better look. I also pulled out my phone and turned on the camera. (I’d rather use a good camera, but I prefer to carry my phone!) This was the best example of a ruffed grouse’s snow roost that I’d ever seen!

Grouse are exquisitely adapted to winter. They grow their own snowshoes in the form of fingernail-like projections on their sides of their toes. Extra feathers on their beak and legs provide insulation where it’s needed. And when their fluffy body feathers aren’t enough, grouse use the snow like it’s a cozy down comforter.

Once there are 10 or more inches of snow on the ground, grouse will dive or burrow into the fluff and spend the night in an air-filled tunnel. Temperatures under the insulating snowpack often reach a pleasant 32 degrees F. No matter how cold it gets, the snow roost rarely drops below 20 degrees F. Research has shown that grouse don’t need to really speed up their metabolism to keep warm until the temps dip below 25, so the snow roost provides them with significant energy savings.

I could see the grouse’s sleeping nook begin where the trough ended. Skiing forward and looking back into the tunnel, I spotted a pile of about a dozen macaroni-shaped scats in the shadows. Yes, I took a picture of the scats! They represent another purpose for the snow roost. In winter, grouse subsist on tree buds and catkins. Trembling aspen buds seems to be the most nutritious—and grouse prefer them—but the buds and catkins of bigtooth aspen, birch, alder, willow, hazel, and ironwood also provide sugar and protein.

There are two main problems with eating tree buds, though. First, they take a lot work to digest. To address this problem, grouse have a muscular gizzard with added grit that grinds up the woody material. From there, the softer materials enter the caeca. These two extra-long pouches contain specialized bacteria that can digest cellulose and absorb more nutrients before the food exits their digestive system. Waste from the caeca ends up as a dark, shapeless plop, while the woody materials become cylinders of molded sawdust like those I found in the roost.

The second problem is that eating buds in the leafless treetops exposes you to the hungry eyes of predators. As many of you know, grouse meat is quite tasty. A grouse’s solution is to eat an entire day or night’s worth of food in about 20 minutes. They store all that food in their crop—an expandable sack at the base of their neck—and then find a safe spot to digest their meal. A snow roost shields grouse from the piercing eyesight of hawks and owls, as well as the sharp noses of foxes, coyotes, bobcats and fishers.

With only my lowly human senses and tendency to daydream, I’m sure the snow roost would have completely concealed its resident from me. If I’d skied by earlier and been the one to flush out this grouse, I would have been completely astonished by the flying snow and flapping wings.

Snow roosts aren’t just an interesting tracking story to read in the snow, though. They are truly a necessity for these birds’ ability to survive the winter. Thin or crusty snow—unsuitable for roosts—makes their brown feathers more visible than no snow at all. While the deep freeze of last week may have challenged our thickest mittens, it also provided perfect conditions for grouse to hide. The balmy temperatures of this week may feel pleasant on bare skin, but they are wrecking the snow for grouse and skiers alike. A 2008 study in The Wilson Journal of Ornithology found that about 17% of the variation in grouse populations is controlled by snow conditions of the previous winter. Deep, fluffy snow equals more grouse. Crusty snow results in a higher mortality rate.

As I skied on (and on, and on…for a total of 50k of Birkie training in two days!) the tracks of weasels, hares, mice, wolves, deer, and squirrels crisscrossed the groomed trails. Just like the grouse—and the dozens of other skiers out on the trails—they have adapted to winter. If you know how to take advantage of it, good snow can be a real boost to your survival.

Special Note: Emily's book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/. Listen to the podcast at www.cablemusum.org!

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: "Nature's Calendar: Signs of the Seasons" is open through March 11.

A Winter Walk with Lois Nestel

As the Cable Natural History Museum enters its fiftieth year in existence, we find ourselves pausing to remember the past as well as dream for the future. In particular, I find pleasure in contemplating the legacy of Lois Nestel, the founding naturalist, director, and curator of the Cable Natural History Museum. Lois was a talented, self-taught naturalist, artist, and taxidermist. Examples of her accomplishments populate every corner of our modern museum building. Her legacy is strong in the work that we do.

I never met Lois, but every Friday I feel a particular kinship with her as I send my “Natural Connections” article off to the newspapers. Lois initiated the tradition of a weekly nature column provided by the Museum, and did so with a gentle, reverent, poetic style. Her column was titled “Wayside Wanderings,” and the articles were compiled into two small volumes in 1975.

One of my favorite authors, Sigurd Olson, provided the introduction to Lois’s first volume. In his characteristic style, Sigurd wrote: “With the eyes of a naturalist, artist, and poet, season by season she has recorded the miracles she found there, miracles that epitomize the truth that we are all part of nature; that because of our primeval background we hunger for simplicities of the past, the beauty of flowers, trees, and animals. Her essays build awareness and open the eyes of children to a world of wonder and delight they may not have known before.”

While I never had the privilege to go on a walk with Lois, her words transport me into a forest that feels absolutely timeless. “It was a perfect day to walk in the woods,” she began, and I’m sure you can imagine it with her. “The first snow had been followed by a warm, sunny day so that the packy snow went “squdge, sqwudge” under foot. Though well-grown and diversified, this forest still bore the scars of long-ago logging. Skid roads, now barely discernible, meandered down wooded slopes toward bogs and ponds. They were primarily game trails now, and little more than occasional cuts and fills were left as reminders of man’s intrusions.”

“The light covering of snow was pierced by winter ferns, ground pine, and club mosses that were unbelievably green by contrast, and where the evergreens were thick the duff was richly brown.

Except for the distant chattering of a couple of squirrels the woods were silent, but the soft snow carried telltale marks that indicated an abundance of unseen life. Where birch trees had fallen and the wood long since crumbled away, the durable bark remained in long crumpled tubes and in and out of these ran the twin dimpled marks of weasels, these often overlaid upon the dainty tracks of mice and voles.”

“A hollow log had housed a porcupine, his droppings and a quill or two inside and outside; where his shuffling feet had pressed the damp snow down, the dye from decaying leaves had turned it yellow-brown. Squirrels had hopscotched from tree to tree and the shards of thousands of hemlock cones were evidence of how busy they and the birds had been.”

“As the trail dipped toward the bog it was crisscrossed by rabbit tracks. Here too, silent as a shadow, a raven, gliding into a pine top, vanished as if it had never been. The tracks of a coyote followed the trail for a while before veering off in the midst of a thick growth of young balsams. Just brushing against these balsams in passing left a scent on clothing that lasted for hours.”

“Woodland ponds were covered with skim ice, but the rivulets draining them still ran free, and along them were myriad small tracks too blurred in the wet snow to be identified. Like unpatterned cross stitching, binding the landscape together, were the tracks of deer of various sizes and even in this shallow snow the toe drags were often apparent.”

“These were some of the things I saw, but how much did I miss? How many unseen eyes watched me? There is never time to peer into every hold, under every flap of bark, behind every stump and tree. The only tangible reminder I brought back was a handful of tamarack twigs with their dainty cones, but long after these are gone the pictures in my mind will live.”

How lucky we are that Lois wrote down these accounts of her wayside wanderings, so that the timeless images can live in our minds, too. Lois accomplished many great things over the years, but perhaps one of the most valuable is her ability to bring us into the woods with her. May the peace of her forest walk stay with you throughout your day.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is open through March 11.

Multi-species Sledding Adventure

The torrential rain on Christmas Day was really a bummer. At my parents’ house in northeast Iowa, we had thunder and ice as well. Once we’d finished Christmas dinner and started opening gifts, though, the weather outside no longer mattered. As the semi-solid drops beat against the garage doors, we drowned it out with the tapping of a hammer on geodes.

The day after Christmas brought better weather, and three kids (well, four if you count me,) high on sugar cookies who needed an outlet for their energy. On went the boots, snow pants, jackets, mittens, and hats. Out came the rainbow of sleds and one snowboard.

Surprisingly, the snow was perfect. Just a thin layer of icy granules blanketed the paths Papa had mowed through the prairie, but that was enough. The sledding hill required no packing, no snowplowing through deep fluff to create a run, and no spray of loose flakes flew up in your face or down your neck. Walking up the hill was a breeze, too, without post-holing on every step.

After a few runs down the old fence line, parallel to a crumbling sentry line of dead elms, we switched to a path cut diagonally across the hill. I loved it. For some reason, I could maintain a straighter line on the side slope, and a sharp drop at the end provided just the right amount of added excitement. Also, I’ve always maintained that sledding is more fun when you yell.

Hiking back up brought even more excitement. There, in the middle of the mowed path, just below the house, was a line of large, 5-toed tracks. I had Zac (age 7) put his gloved hand in one: perfect fit.

Obviously the snow wasn't on a wall, but I can't get the program to allow this photo to upload horizontally!

Had I been in Wisconsin or Minnesota, my first thought would have been fisher. Animals in the dog and cat families have four toes. Weasels, bears, and raccoons have five. But that large weasel doesn’t live in Iowa. As I followed the trail of the 5-toed animal looking for more clues, I came upon a well-preserved pair of tracks—the first one short and roundish, the second one elongated like a child’s foot. I stared in disbelief and shook my head. Bear? Bear! In Iowa?

It’s actually not out of the question. Although Iowa is part of bears’ historic range, like many species, they were pushed out as the land became more settled. Just last June, though, my friend Brian Gibbs spotted one about 30 minutes from our sledding hill, and the Iowa DNR confirms about five black bear sightings a year. The working hypothesis is that as populations in nearby Minnesota and Wisconsin grow, antsy young males travel farther in search of food and females. I like the idea of my new Wisconsin home providing species to my old Iowa home.

I wasn’t sure how the kids would react, but I had to tell them. “I think these are bear tracks, guys!” I said, and we all admired the tracks for about two seconds. Then the sledding resumed, and soon the perfect tracks were obliterated. Oh well.

After sledding, Zac and I found Papa in his workshop and announced our discovery. We went out for a second look. The three of us picked up the 5-toed tracks at the bottom of the hill, and started following their trail. All the tracks seemed shorter now, like the bear had four front feet. The trail wasn’t very wide, either—not like a broad-chested bruin. And then, across a straightaway, the messy trail resolved into a neat, two-by-two bounding pattern leading away from a trough pressed into the snow on the hillside. The bounding is classic in the weasel family. The trough clinched it: otter. In winter, their favorite gait is run-run-run-sliiiiiiide, and I couldn’t help but smile at the fact that this otter also was sledding down our hill.

While otters, like bears, were extirpated from Iowa, otter reintroduction efforts began in 1985. Live-trapped wild turkeys were shipped from Iowa to Kentucky to help its restoration program. Kentucky sent cash to Louisiana, and Louisiana shipped otters to Iowa. In total, 345 otter were released in Iowa between 1985 and 2005. Today, the population is stable enough for a limited fur harvest.

Overland travel is not out of the ordinary for otters as they navigate between watersheds. They can travel up to 26 miles in a day, with 5-6 miles being average. Females and their young stay together in family groups, and males will form their own groups, too. We followed the tracks back up the hill, across the road, through the end of the orchard, and to the edge of a briar patch on the bluff above the Turkey River. We stopped there, confident now that there were actually two otters, and that they were headed to the river for a fishy snack.

Mystery solved, tired and warm from sledding and our hike, we headed away from the river, looking forward to a non-fishy snack.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/. Listen to the podcast at www.cablemusum.org!

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is open through March 11.

Rocks in Our Socks

What did you have on your list when you climbed onto Santa’s lap this year? If you were one of my brother’s kids, you asked for rocks. “Anything else?” Santa pressed on. Rocks and dirt. Kids after my own heart! We are the Stone Family after all. While Santa may not have delivered, Auntie Em and Grandma did!

The dirt is a relatively new request. Derek, 12, has been honing his gold panning skills, and wanted a new batch of Pay Dirt—complete with flakes of real gold—to pick through.

The rocks are a different type of treasure. Somewhere along the line we introduced the kids to “crack your own geodes.” These bland-colored, roundish rocks look positively dumpy on the outside. Whack them with a hammer, though, and they split open to reveal an airy chamber lined with sparkling crystals. What’s not to love about a tradition that includes hitting and breaking things, the joy of surprise, and sparkles all in one?

This year I wasn’t expecting much. The geodes I purchased at our Museum Shop were sallow, plain, and small. I was worried they’d be duds. Derek wasn’t discouraged, however; in his experience, these boring-looking ones have produced the best crystals. I brought four geodes, hoping that Isaac, 14, our original geode cracker, would put down his smart phone long enough to break his own. No such luck. He’s now a power tool addict waiting for the day when he owns a diamond saw and a way to hold the rocks for slicing. When that happens, watch out! Every rock in their extensive collection will be sliced open, anticipating the discovery of some spectacular inner beauty.

The three younger kids and I put on shoes and safety glasses and headed into the garage. We rummaged on Papa’s work bench until we found a hammer and chisel, and let the cracking commence.

Derek is the lead rock hound now, and he cracked the first one. It popped open easily, revealing a delicate lining of clear, glittering, crystals. “Ohhh and Ahhh,” we exclaimed appropriately. He also cracked Isaac’s geode, and the kids dutifully set it aside for their big brother after admiring the sparkles. Next, Zac, 7, the rock cracker’s apprentice, took his turn. The geode rolled around a bit under his tentative hammer, and Derek bravely helped him out by holding it steady. His fingers survived! A crack formed, and one more gentle tap split it open to an admiring chorus. Somehow, the anticipation and revelation never gets old. After Derek helped Zac’s twin, Kylee, split hers, too, they all trouped back inside to show Grandma.

Derek’s prediction had been correct: these unassuming geodes all held beautiful crystals, and the kids declared this the best round of Christmas geodes yet!

Curious as to where these splendid geodes came from, I looked up the purchase order. “Moroccan geodes” was their exotic title. This little country at the northern edge of Africa hasn’t seen a glacier in ages, so the rocks there have had time to weather at the surface. The region boasts some cool geology. Morocco’s geodes were formed in basalt—just like our Lake Superior agates. But the photos of Moroccan basalt look nothing like the glacier-polished North Shore. The African rock is crumbly and brown from ages of oxidation and weathering.

Geodes occur closer to home, too. They are the state rock of Iowa! The epicenter of Iowa geodes is in the far southeastern corner, in a 35-mile radius around the town of Keokuk, including parts of Missouri and Illinois. This world-renowned site sits on the lower Warsaw Formation, which was deposited as mud in a shallow sea 340 million years ago, and lithified into shales and limestones.

It doesn’t matter if geodes form in basalt or limestone; they still need a cavity to start with. The holes in basalt were created when gas bubbles formed in the cooling lava. The holes in the Iowa limestone have a more complicated origin. They began as concretions, which are the opposite of geodes. Concretions formed when minerals hardened around some nucleus in the mud, creating a nodule. After the chemical composition and acidity of the surrounding water changed, a cryptocrystalline type of quartz replaced their outer shell. Next, the inner, more soluble minerals of the concretions dissolved and left a hollow space. Finally, over thousands to millions of years, mineral-rich groundwater percolated through the space and precipitated sharp-angled crystals of quartz from the walls of the cavity inward.

Sometimes other minerals will join the mix and expand the color palette. As in agates, these colors occasionally form concentric bands. The difference between agates and geodes is that agates are created when cavities in the rocks are filled with patterns of colorful cryptocrystalline quartz, while geodes grow visible crystals (not always quartz) into a hollow center.

In any case, getting rocks in your Christmas stocking can be a pretty fun tradition. With the Stone kids, I think that even a shiny black lump of coal would be a treat!

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is open through March 11.

Just Ducky

The bitterly cold wind numbed my cheeks, stung my eyes, and blasted my half inch of exposed forehead with an ice cream headache. Happily, the sun was shining and the rest of my body—entombed in layers of wool and down—remained a comfortable temperature. As they say, there is no bad weather, only bad gear. I felt adventurous to be out walking on this sub-zero day, even though the temperature had risen a full 14 degrees from -17 to -3 degrees Fahrenheit.

With the wind at my back, an ethereal sunset glowing on the horizon, and a warm house waiting less than two miles ahead, I decided to take Duluth’s Lakewalk along the shore of Lake Superior. Ice and snow mingled with rocks on the beach, and although no ice floated in the lake, the water looked frigid just the same. NOAA data shows that the temperature in this corner of the lake is about 40.5 degrees, which is just a tad warm for late December.

As I rounded the corner by Endion Station, I was surprised to see life. Dozens, maybe hundreds, of mallard ducks huddled in rafts along the leeward shore, the iridescent green heads of the drakes shimmering handsomely in the last rays of sun. They looked especially dapper against the pure white patterns of ice-draped riprap. The presence of this concentration of life somehow made the afternoon feel warmer.

Don’t ducks migrate south for the winter, though? Well, as with so much in nature, it depends. Mallards are medium-distance migrants, who only go as far south as needed. Some do fly all the way down to Mexico and the Caribbean, but many seem to prefer a “staycation.” About 1,500 mallards even make Anchorage, Alaska, their year-round home! As long as the ducks can find sufficient food, they can withstand some pretty brutal winter weather.

In species of songbirds who are medium-distance migrants, such as red-winged blackbirds, and juncos, it tends to be mostly males who overwinter farther north. For them, being the first back on their summer breeding territory is of utmost importance.

That’s not the case for mallards. Although this flock seemed to have a few more males, that’s likely due to a male-heavy skew in the overall population. Male and female ducks need to overwinter in mixed flocks, because that’s when they choose a mate and form pair bonds. In spring they arrive on their breeding territory together. Once copulation is complete, though, the males disperse. The female incubates the eggs and protects her clutch of fuzzy nuggets all by herself. (Insert your favorite joke about lazy males here.)

Continuing up the ramp to where the path parallels the railroad tracks, I looked down into a small pool—hidden in the riprap—that seemed to be at the outlet of a culvert. Here, out of the wind and in water that was potentially slightly warmer, ducks carpeted every surface. Pulling my scarf up over my windward cheek, I stopped to watch.

Some ducks floated with their beaks and heads tucked backward under their wings. My rosy nose was envious. Other ducks paddled idly in circles, perhaps a little off-kilter because one foot was being warmed up in their feathers. Occasionally one or two ducks would start dipping their heads quickly and letting the water slide cleanly off their backs. It didn’t match the feeding behavior I’ve come to expect from dabbling ducks: pointy tail sticking straight up in the air for several seconds while their beak probes the bottom. Mallards use a similar dipping motion in their courtship rituals, but that looks more like a head bob than this dolphin dive. It reminded me of how I feel in an outdoor hot tub, constantly submerging myself in the water to stay warm. Could it be that the ducks are using the “warm” water (more than 40 degrees warmer than the air!) to help maintain their body temperatures?

Plenty of ducks weren’t even in the “warm” water; instead they huddled on a small shelf of ice at one end of the pool. They looked cold. But looks can be deceiving. Mallards are big-bodied ducks, and well able to maintain their 100-degree body temperature. All of our winter parkas imitate their fluffy, warm, down feathers protected by a waterproof shell. We can’t even come close to imitating their feet, though. Not only are webbed duck feet adapted to swimming, they are adapted to manage heat loss as well.

Mallards have blessedly few nerves in their feet. They don’t seem to feel the excruciating pain of too-cold toes warming up. The discomfort that humans feel is actually a helpful adaptation, though, and inspires us to warm up our feet or hands before they are damaged by the cold. Ducks don’t need that motivating pain to keep their feet safe. They have a net-like pattern of veins and arteries in their feet, called “rete mirabile,” which is Latin for “wonderful net”. This wonderful net allows cold blood returning from the feet to be warmed up by outgoing blood before returning to the body. Ducks will increase or decrease blood flow to protect against tissue damage while losing as little heat as possible to the environment. They may not feel as cold as they look!

Flocks of mallards in the open water near Duluth are a common winter phenomenon, at least in recent memory, and they seem to have the adaptations to handle an Arctic blast. I think they probably would agree that there is no bad weather if you have the right gear.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Silver Lining

Perfectly firm, freshly groomed tracks cradled our skis. Bright sun warmed our faces despite an occasional breeze. A sinuous, brown and white river caressed our looping length of trail. And a half-tunnel of arching tree branches cupped us in their arms. The River Trail at ABR ski touring center in Ironwood, MI, was treating us well for this first long ski of the year.

I paused at an intersection to let my companions catch up, and found myself admiring a line of trees perched on the bank of the Montreal River. Each tree was actually a cluster of trunks, united at the base and spreading gently out toward space and sunlight like a giant, woody bouquet, with bright snow accentuating each curve. Round, red buds adorned the tip of each oppositely arranged twig, giving its crown a polka-dotted look. Gliding up, Abett asked about the tree, and I shared “silver maple” as my identification. We all admired their form.

Silver maples are classic floodplain trees in Wisconsin, and this wide, flat area along the Montreal River is perfect habitat for them and for easy ski trails. In its other reaches, the Montreal River cuts through cliffs, crashes over waterfalls, flows under the deep shade of conifers, and pours out on to a rocky Lake Superior Beach. The Ojibwe name for the river is Gaa-waasijiwaang, meaning “where there is whitewater.” It’s true that most of the water I see is white, but for a different reason. Here, (as far as I can tell under the snow) it meanders through alder thickets and grassy meadows that are soggy when not frozen.

While the dark, tannin-stained waters of the river look innocuous where they peek out through holes in the ice, they probably aren’t always so well-behaved. I cite the trees as my evidence.

The tight grouping of trunks exhibited by these silver maples is a common form among floodplain trees, and is shared by basswoods, too. Silver maples drop their helicopter seeds (the largest of any maple) in the spring. The seeds may get a wild ride to a new home if there is a flood, and the well-provisioned little explorers germinate immediately. In the moist, rich alluvial soil of the riverbank, they might spend a season or several growing straight, tall, and independent. Until another flood comes. Debris, logs, and even ice churn down the river and over its banks. The little tree doesn’t have much of a chance.

Luckily, silver maples—especially small trees less than a foot in diameter—can resprout prolifically from their stump or root crown. With an established root system already in place, I bet the second round of sprouts grows even faster than the original. By the time the next flood hits, the trees are already in defensive position, with the upstream trunks shielding the downstream trunks from damaging debris.

The roots of a silver maple aren’t just important for resprouting after damage. Any plant that lives near water needs to be adapted to having its feet wet. Even roots need oxygen in order to carry out respiration and grow. On the other side of the trail, a thicket of speckled alders takes in extra oxygen through the many lenticels (“speckles”) in their bark. They transport that oxygen to their roots. Earlier, we’d skied under a big, arching willow tree with its gnarled branches and graceful, yellowish twigs reaching all the way over the trail. Willows also use lenticels to breathe. Silver maples take a different route, and send a shallow root system near the surface where there is more oxygen.

Despite growing right next to the river, these silver maples were actually perched on slightly drier soil than you’d find a few yards inland. When a river floods, the moment its water spills over its banks, it slows down and deposits the biggest pieces of its suspended load—sand. This process builds a raised bank—a natural levee—between the river and its floodplain. So, instead of dipping their toes in the soggy muck beyond, the silver maples lined up on the natural levee can take advantage of both well-drained (and oxygenated) sandy soil, and the proximity to water. Meanwhile, their fortress of trunks protects them from the river’s fury. This is yet another example of teamwork in a forest.

Our little team of skiers continued on shortly, after exclaiming a few times about the beautiful weather, the perfect grooming, the fine company, and this gorgeous scenery. There wasn’t a cloud in the sky, but our ski even had a silver lining.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.

Snowflake Birds

Big, fluffy, wonderful snowflakes swirled around my head and the stiff breeze sent icy fingers down my neck. Slamming the car door against the storm, I started the engine and wished the temperature gauge would rise above cold so I could turn on some warmth. My cross country skis were rattling around behind me—ready, but unused—so I was ecstatic about this storm, but the cold was still a shock to my system.

Rolling along the highway at a relaxed, “get-there-safely” pace, I enjoyed the scenery’s face lift. Drab, brown fields have been transformed, and the forests are delightfully frosted. Tawny, dried weeds and their dusky shadows painted texture on the roadside border, which gave way to glittering fields of smooth white. Suddenly, those colors came alive in a cloud of swirling beauty. Brilliant white, sharp black, brown, and blur; the flock of snow buntings ascended, swooped as if tossed by blizzard winds, and flashed their colors in unison as I passed.

The warm brown srtipes on snow buntings are only temporary, and are confined to just the tips of feathers. All winter, the male rubs his feathers on the snow, wearing off the brown tips and revealing his dapper white and jet black courting suit by the time breeding begins. Females also rub off most of their brown tips. Photo by Charles J Homler, creative commons.

These tough little visitors from the Arctic live up to their nickname of “snowflake birds.” They nest on tundra all around the top of the globe, and are the most northerly recorded songbird in the world. In fact, one scientist claims that “Under the current climate conditions of the Arctic, there is no northern range limit for snow buntings.” There is a southern limit to their range, though, since a certain amount of daylight is essential to their reproductive success. They also require the average temperature in July to stay below 50 degrees F. That may sound unpleasant to you, but it comes with midnight sun, a warm down jacket, and the stark beauty of places like Ellesmere Island, Greenland, Norway, and Siberia.

In winter, some snow buntings (especially females) head as far south as Iowa or Utah, but some (especially males) migrate only as far as northern Canada. Moderate cold isn’t an issue. They can survive in temperatures down to -40 degrees F. Only when it gets down to -58 degrees F does their body temperature start to plummet. The solution? Dive into a nice, warm snowdrift. The insulating power of snow helps preserve their body heat and keep out the wind.

My toes get cold just thinking about it, but feathered feet allow snow buntings to spend most of their winter strutting about on the chilly drifts. They usually feed in big, gregarious flocks that seem to roll along chaotically as the birds in the back make short, fluttering flight to the front. Occasionally, the whole group will rise and fall in a flurry of motion at the suspicion and passing of danger. Feeding flocks are entertaining to watch, since these birds don’t submit to a defined hierarchy like chickadees do, and end up bickering continuously over seeds and space.

Deep snows cover up the seed heads of short tundra plants in their breeding territory, but here in Wisconsin, snowplows expose seeds in the gravel shoulder, and windswept fields of nodding stems offer good foraging, too. I was particularly happy to read that they eat seeds of the ragweed plant, which is a major cause of seasonal allergies!

Naturalist John Burroughs wrote that snow buntings have “plumage copied from the fields where the drifts hide all but the tops of the tallest weeds, large spaces of pure white touched here and there with black and gray and brown.” But some colors are only temporary, and are confined to just the tips of feathers. All winter, the male rubs his feathers on the snow, wearing off the brown tips and revealing his dapper white and jet black courting suit by the time breeding begins.

This is an odd way to get dressed, for sure, but it saves valuable energy that would be spent on the usual second molt. And energy is at a premium in spring. Snow buntings must gain at least 30% more body mass before beginning their northerly migration, and individuals without adequate energy storage don’t seem to be able to “select seasonally appropriate directions during their migration.” In other words, skinny birds can’t find their way home. Perhaps this keeps them in warmer regions until they have gained enough strength to migrate.

The ones that do head north fly at night and use the geomagnetic field of the Earth almost exclusively for wayfinding. Visual clues are of little use to them in the blank, white of the tundra. Males arrive on their breeding territories in early April, when temperatures can still drop to -22 degrees F. They have to arrive early to secure a good territory, since the cracks and cavities in rocks where they nest are a finite resource. Females, sensibly, arrive six weeks later. He woos her by singing fast and often—a signal that he is an efficient forager and has ample free time for lovesick serenades. That’s important, because she must incubate the eggs almost continuously to keep them warm in the cold rocks, and relies on a fast-foraging male to feed her during that period.

The breeding season is a long way off, but today it feels like the snow buntings have brought the tundra south with them. I would agree with John Burroughs, who described them as “the only one of our winter birds that really seems a part of winter, that seems to be born of the whirling snow, and to be happiest when storms drive thickest and coldest…”

Arriving at the trailhead, I emerged into the swirling flakes, clicked into my skis, and attempted to embody the spirit of our tough, adaptable snowflake birds.

Special Note: Emily’s book, Natural Connections: Exploring Northwoods Nature through Science and Your Senses is here! Order your copy at http://cablemuseum.org/natural-connections-book/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! Our new phenology exhibit: “Nature’s Calendar: Signs of the Seasons” is now open.