Red-winged Blackbirds

When springtime starts with sloppy mud, gray skies, and tepid weather, it’s hard to get excited about the season. No sound is better able to pierce this wet blanket than the ringing konk-la-ree call of a red-winged blackbird with its thrilling trill at the end. I’ve heard it everywhere lately, from a lakeside bike ride to my walk from car to office.

Red-winged blackbirds are year-round residents in much of their range, which stretches from the Yukon down to the Yucatan. The northern breeders, though, must migrate far enough south to find crop stubble with waste grain and weed seeds not buried by snow. They gather in large flocks of as many as several million birds, and fly up to 50 miles each day from the roost to foraging grounds.

For red-winged blackbirds in the Great Lakes region, this generally means about a 700-mile trip. That’s not far in comparison to our “neotropical” migrants like hummingbirds, flycatchers, thrushes, and warblers who fly thousands of miles to overwinter in Central and South America. Those birds are nectar or insect specialists, and can’t eke out a winter survival on seeds alone.

One advantage that staying in the neighborhood gives red-winged blackbirds is that they have a better idea of how this particular spring is progressing, and can adjust their migration schedule based on weather. Neotropical migrants have no way to tell that spring is coming early in the north, so they stick to more stable cues—like day length—to decide when to migrate. Weather still affects their progress, since a winter storm or unfavorable winds can cause a delay, but their timing tends to be more consistent.

Red-winged blackbird males overwinter even closer to home than the females, because they have good reason to get back north as early as possible. The first male often gets the best territory, and it’s their gloom-piercing call that seals the deal. Belligerent males display in a “song spread” that includes fluffing up feathers, spreading their tail, raising their shoulders, and flashing their red epaulets, all while singing at the top of their lungs. We may appreciate this colorful performance, but it is not friendly, and it is not for us.

While the flocks of males currently foraging in yards and under bird feeders are not on territories yet, they already singing loudly—warming up for the big show. Drab, brown females will follow later, after insects begin to hatch. The ladies need a high-protein, high-calcium diet to prepare for egg laying, and have no reason to risk getting caught in a blizzard.

Once they arrive, females will choose a male’s territory, and set up a smaller territory within it. As many as 15 females might nest in a single male’s territory, but the average is five. Nests are built low to the ground, and are suspended among some upright stems of marsh plants. Females wind stringy plant material, wet leaves, and decayed wood into a bowl, and the line it with soft, dry grass.

This habitat requires a couple special adaptations. The most visible is the brown-streaked plumage of the females—perfect for staying camouflaged in the thickets. Those feathers are also extra sturdy, because living among rough cattail stems could result in undue wear and tear. In addition, both sexes have sturdy leg muscles that allow them to perch with each foot on a different cattail and do the splits.

Red-winged blackbirds also have long digestive tracks, which allow them to eat a wide variety of foods. In the summer, though, when their diet focuses on insects, their gizzards will shrink, only to get more muscular again when late summer seeds become ripe.

Late summer seems worlds away, though, as snow falls in the mud puddles and weed seeds get re-buried. The migrating flocks of red-winged blackbirds must be on the move again, looking for spring. When they find it, we can be sure they’ll sing a ringing konk-la-ree to let us know.

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” will open May 1, 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Red-winged blackbirds are an early spring migrant, and pierce even gloomy days with their ringing call. Photo by Larry Stone. 

Hot and Cold for Spring

During the fickle days of early spring, my emotions seem to rise and fall in sync with sap in the maple trees. I get kind of grumpy when the mornings dawn damp and cool and the tracks on the ski trails sink dejectedly into the slush. After the extended ski seasons of the past two years, I’ve gotten accustomed to having endless days to explore new trails and perfect technique.

My feelings change as the days brighten, intense sun takes over, and the temperature spikes. Warm breezes and dry roads make me eager to put away the skis, and happy to pull my road bike out of storage. I guess you could say that I’m running hot and cold for spring.

The first place I head on my inaugural spring bike ride is to a little wetland across the county road from Lake Namakagon. This wetland tends to thaw a bit sooner than the one by my house and it is consistently the first place I hear the spring chorus of frogs.

The eleven species of Wisconsin frogs (and one species of toad) wake up and begin singing their songs in a typical order each spring. Their specific phenological timelines depend on things like overwintering location, cold tolerance, and breeding habitat.

Our three earliest singers share some common characteristics. Wood frogs, chorus frogs, and spring peepers are all somewhat terrestrial frogs that spend the winter as frogcicles, buried lightly in duff on the forest floor. Spring sun and warm rains can reach them quickly here, and they are triggered to thaw, wake up next door to their honeymoon suites, and breed very early in the season. April is typically their main month of romance, but each spring progresses a little differently.

By getting such an early start, these frogs are able to carry out their entire breeding cycle in vernal pools. These woodland puddles only persist for a few months each spring. This means that eggs and tadpoles don’t have to worry about the fishy predators who would live in a permanent body of water, but it also means that the parents need to hurry up and get their babies growing so that they can gain legs before the pool dries up.

Of course, spending winter on land has its own challenges. Even though the subnivean layer—where snow meets earth—remains warmer than the television weather report, frogs in the duff must still endure below-freezing temperature for many days at a time. They do this not by avoiding the frogcicle state, but by guiding it.

Wood frogs are the most highly studied, but spring peepers and chorus frogs use similar techniques. The process starts early in fall, when wood frogs begin accumulating urea in their tissues. While urea is a waste product that humans excrete in our urine, urea is also a cryoprotectant, or a substance used to protect biological tissue from freezing damage.

Then, when the temperatures dip below 32 degrees Fahrenheit, ice crystals start to form on the frog’s skin. Some animals are able to “supercool” or prevent the formation of ice even when temps dip below freezing. This usually requires them to avoid contact with ice that would trigger flash freezing. Frogs, with their permeable skin, just allow the frost to set events in motion.

Ice formation causes the frog’s liver to convert stored glycogen into glucose. The sugar floods throughout the frog’s body, carried in its bloodstream by a heart that keeps beating as long as possible. As ice forms outside of cells, it locks up the pure water, and leaves behind a higher concentration of salts and other things that were previously dissolved in the liquid. Water from inside the cells wants to flow outward, across the cell membrane, to even out the imbalanced concentrations.

This could dangerously dehydrate the cells, though, and there is a threat of them collapsing. Glucose and urea help the cells retain water in two ways. First, sugar water freezes as a lower temperature than plain water, and so less ice forms overall. Second, by increasing the concentration of chemicals inside the cell, it keeps water from wanting to flow out of the cell under osmotic pressure.

While frozen, the frogs are essentially dead.

Once spring comes, however, wood frogs thaw from the inside out. The heart starts beating (scientists still don’t know what jumpstarts it), the brain wakes up, and finally legs move. And those legs will carry them directly to a nearby vernal pool. A deafening chorus of love songs ensues, and mating commences in a hurry. Wood frogs quack, spring peepers jingle like bells, and chorus frogs imitate a finger plinking a plastic comb.

That’s what I was hoping for today, but the wetland was still quietly blanketed in snow. Over the winter, the frogs may undergo multiple freeze-thaw cycles. Springtime warmth also ebbs and flows. And then there’s me, sometimes turning a chilly shoulder to our next season, and sometimes embracing it with an open sweater. I guess I’m not the only who runs hots and cold!

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” will open May 1, 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Wood frogs are hardy winter hibernators and early spring singers. You can identify this small brown frog by the black bandit mask across its eyes. Photo by Michael Zahniser, Wikimedia Commons. 

A Prickly Botanist

A dozen adults hunched over tables examining bare twigs with borrowed hand lenses. Back and forth they looked, between the dichotomous key and their specimen. Did it have one or three bud scales? Or more than five bud scales? Was the pith of the twig chambered or solid or hollow? Finally, we arrived at an answer: the smooth, gray twigs with plump, red buds (covered by three bud scales) belonged to a basswood tree. For fun, I had the students each nip off a bud with their teeth and experience the slightly sweet flavor and mucilaginous texture of this wild edible.

We practiced keying out a few more twigs, and then the winter tree identification class headed eagerly out into the warm sunshine to walk the trails at the Northern Great Lakes Visitor Center in Ashland, Wisconsin. We sniffed the glossy, aromatic buds of balsam poplar, admired the snazzy, scarlet stems of red osier dogwood, and commented on the stalked buds of speckled alder. Identifying woody plants by their winter twigs is one of my favorite challenges, and I hoped that the students would gain an appreciation for it, too.

As I drove home on Highway 2, a dark blob high in a roadside tree caught my eye. One quick glance backward confirmed my suspicion. The blob showed a spikey outline against the evening sky. Porcupines have begun their spring feast!

If you want to meet a real expert in winter tree identification, be sure to bring a thick leather glove for shaking their paw. Porcupines survive on low-nutrient bark all winter long, and the lengthening days of spring bring a welcome change in their diet. A few years ago I started noticing that in late winter these bristly roadside silhouettes start appearing with some regularity. As it turns out, porcupines spend their spring eating a rotating smorgasbord of juicy tidbits, and they time their courses to match the period when each entree is the most nutritious. They know their trees well because their life depends on it.

Dr. Uldis Roze, professor emeritus at City University of New York, radio-collared a porcupine he named Rachel, and followed her around the Catskills one spring. By testing the chemical content of the buds and leaves while Rachel fed on them and then analyzing the plants again after she ceased to eat them, Roze discovered that Rachel pinpointed plant parts high in protein and low in toxins.

To get at the most nutritious parts of a twig, porcupines will balance out toward the terminus of a branch and nip off its end using their self-sharpening incisors. Turning the wand around, they nibble off all the most tender twig tips and buds and then discard the rest. Trees on sunny roadsides may be further along in their seasonal sequence than their relatives in a shady forest, so porkies are extra visible now as they satisfy their hunger for spring.

Sugar maple buds are one of porcupines’ first spring snacks. As sap rises, the buds swell. Packed inside the overlapping layers of toffee-colored bud scales, tiny leaves and twigs begin to expand. Their chemistry changes, too. At the height of their nutrition (which happens just as the syruping season ceases), sugar maple buds have more protein than enriched breakfast cereal.

After just a few weeks, once the buds have fully released their tender young leaves, porcupines cease their sugar snacking totally. The protein content might still be the same, but it no longer matters. The tree has now fortified its appendages with toxic tannins. Tannins are chemicals that bind with proteins, making them an effective defense against many types of herbivores.

Sugar maple’s close cousin, the red maple, defends its buds, twigs, and leaves with tannins year-round. It doesn’t seem to have a place in the porcupine’s buffet. Instead, the sweet basswood buds that the students tasted are a porcupine delicacy, as are expanding aspen and willow catkins.

Ash trees are the last to open their buds, and they also represent that last of the spring smorgasbord. Once the juicy expanding packets of ash leaves get too old, porcupines switch to a diet of ground plants for a couple months. When the dandelions, clover, and raspberries dry out, porkies head back up into the trees and return to their winter diet of tree bark and evergreen needles.

Phenology is the study of when specific events happen in nature from year to year in a specific place. Each tree species has its own place in nature’s calendar. Porcupines follow this schedule closely, since each species has an optimum nutritional stage. Amazingly, porcupines are active mostly at night, and so identify their next meal by bud and twig under the cover of darkness. Perhaps my next tree identification workshop should include a pricklier instructor!

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” will open May 1, 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Porcupines are especially visible in spring as they dine on a smorgasbord of tasty tree buds. Photo by Larry Stone.

Traffic

I could not believe the traffic on my driveway this morning. The woods were suspiciously quiet by the time I strolled along it, but the light dusting of fresh snow recorded the secrets of a busy night.

Red fox tracks—about two inches long and sporting claw marks—trotted evenly down the north side of the tire tracks. I followed them absentmindedly through the brisk wind and strengthening sunshine.

At the road intersection, I found the loping 1-2-1 track groups of a fisher. One front paw landed first, by itself in the back of the group (1). Then the other front paw and one hind paw landed side-by-side in the middle (2). Finally, the last hind paw left a single track at the front of the group (1). The dusting of snow atop a firmly packed snowshoe trail made a perfect tracking canvass. Each of the five naily toes registered clearly, and along with the track pattern, gave away the fisher’s identity.

On my way back in, I was startled to see another line of two inch long tracks, each with a slightly different shape than the fox’s. While the fox’s toes were arranged symmetrically, and its interdigital pad was roughly triangular, these other tracks seemed slightly askew. Rounded toes—lacking claw marks—formed an off-kilter half-circle in front of a lobed pad.

I wasn’t surprised to see these bobcat tracks, since we’ve seen the actual bobcat for three mornings in a row. Yesterday, the cat tracks emerged from under my car! My housemate spotted it later on the road. Three days ago we watched the bobcat trot down the driveway, and I later tracked it for close to a mile.

I often notice an increase in tracks this time of year. Perhaps it’s because I’m out in the woods more—enjoying the longer days, warmer weather, and firm base of snow. But I suspect that animals themselves are more active, too, and for some of the same reasons. Plus, this late winter/early spring season is when many animals start traveling more widely in search of mates. For animals in the Northwoods, the timing of reproduction must find a delicate balance between missing the last snowstorms and cold snaps, while still having enough time to grow and be ready for the next round of winter weather.

Red foxes are no exception. In Wisconsin, they tend to breed in January and February and have their pups in March. Males stick around to help care for the young, and a pair will often defend its territory together all winter. I’ve only seen the tracks of a single fox, though, and no musky-smelling scent marks that typically define a territory. Perhaps this fox is lonely and still looking.

The fisher tracks out by the road were solo, too, but that’s not as surprising, based on their breeding system. Male and female fishers don’t socialize throughout the year. The males defend a large territory, often encompassing the range of more than one female. Once a year, around this time, they come together just to mate. Nothing happens right away, though. Once fertilized, a blastocyst (the precursor to an embryo) just hangs out for 10 months. Active pregnancy finally begins in mid-February of the following year. About 50 days later the kits are born. A week after giving birth, the female comes into estrus and the breeding cycle begins again.

Not only are fishers restless from hormones right now, they also enjoy the relative ease of travel on late winter’s crusty snow. One research study found that they become homebodies when deep, soft snow makes travel difficult.

Bobcats are also solitary throughout most of the year, except when they come together to mate in February and March. Males tend to have larger territories of about 25 square miles that overlap with more than one female’s smaller ranges. If my new neighbor is wandering in search of a mate, I might get to hear the yowls, screams, and hisses they use during courtship. Both males and females might mate with more than one partner, and the female raises her kits alone.

As the busy traffic in my driveway shows, late winter is a great time to start planning for the babes of spring. Now, if you’ll excuse me, I have some tomato seeds that need planting.

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 exhibit: “Lake Alive!” opened May 1, 2015, and will remain open until March 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

The rounded, clawless toes and off-center arrangement of bobcat tracks make them distinctive. Bobcats are out and active, searching for mates, during February and March. Photo by Emily Stone. 

Mullein

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 stalk 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 just as dead (actually, even more dead) as its dormant neighbors, its 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 small 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.

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.

That’s just the beginning. The flowers will make a yellow dye. Many parts of the plant are considered medicinal, especially for upper respiratory ailments. The seeds are not edible, but contain chemicals used to stun fish. The fuzzy leaves can be soaked in fat and made into candle wicks or torches, or laid in your shoes for cushioning, or rubbed on your cheeks for “Quaker rouge.” Turns out, the tiny hairs are a skin irritant. They can either make you a blushing beauty, or give you contact dermatitis. Beware of the wide basal leaves’ other use as “cowboy toilet paper.”

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.

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.

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 exhibit: “Lake Alive!” opened May 1, 2015, and will remain open until March 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Can you find it? A black-capped chickadee has cached a hulled sunflower seed in the dried flower stalk of a mullein plant. Photo by Emily Stone

Can you find it? A black-capped chickadee has cached a hulled sunflower seed in the dried flower stalk of a mullein plant. Photo by Emily Stone

Wild Geese

A chorus of sharp honking sent shivers up my spine. Looking up over the nested rows of suburban homes, I scanned the low, gray sky until the V of geese came into view. Their wild calling seemed out of place in my brother’s orderly, central Iowa neighborhood, and my brain flashed back to a crisp September day in the Boundary Waters of northern Minnesota.

Three canoes floated among yellowing lily pads and tree reflections in a cozy bay, while the fourth canoe landed and began unloading for the portage. My dad was the first to hear the geese, as usual. He’s always been tuned in to their music. We all shifted expectantly toward the sound, gently sculling paddles and maneuvering boats to ease the strain on our necks, but saw only the dense spires of spruces and blue sky.

A few moments passed before the flock’s vanguard came into view, and they pulled their followers forward until the long ends of the V trailed over our heads. Taking stock of the early afternoon sun over my left shoulder, I noted with satisfaction that the geese were heading south. The urgency we imagined in their voices felt appropriate after our trip of windy days and chilly nights. We, too, would soon head south to wait out the winter with warm beds and plentiful food.

Our romantic notions of migrating flocks Canada geese as the forerunners to fall and the harbingers of spring are not as accurate as they once were, though. In the 1940s, most geese were migratory, and Aldo Leopold wrote eloquently in A Sand County Almanac about “the geese that proclaim the seasons on our farm…” “One swallow does not make a summer,” he declared, “but one skein of geese, cleaving the murk of a March thaw, is the spring.”

So what was this skein of geese doing—flying north, no less—in February, in a subdivision, less than 150 miles south of the latitude of Leopold’s shack?

As humans have changed the landscape and the climate, some of the 11 subspecies of Canada geese have changed their patterns to match. Many geese who breed in the far north do still migrate long distances. Other northern populations migrate, but don’t travel as far south. The southernmost breeding populations don’t participate in winter migration at all. This shift may be due to newer farming practices that leave more waste grain (a favorite food of geese) in the fields, more year-round open water near dams or industries, and a decrease in snow cover on the tasty grass of our lawns, golf courses, and parks. My guess is that the honking flock over suburbia was headed north to the Saylorville reservoir, or to the windswept farm fields disappearing under the creep of development.

Living near people has proven to be beneficial to the resident geese, since cities provide tender green lawns with a wide-open view, a reduction in predators (including human hunters), and occasional supplemental feeding. Migrating geese must contend with the treachery of travel, predation, storms, and hunting. Their numbers seem to be held in check, while the resident geese are an increasing nuisance and hazard.

Goose poop bringing coliform bacteria to swimming beaches and drinking water, and crop damage are two complaints, but it gets more serious than that. Some resident goose populations crowd out other migratory waterfowl in the wildlife refuges that were created to support them. In 2012, there were 240 goose-airplane collisions, and in 2009 a flock of geese took out both engines on a US Airways plane and forced the pilot to make an emergency landing on the Hudson River.

What’s fascinating, though, is that almost all geese—migratory or not—make short journeys north in late summer after breeding to munch on plants in an earlier state of growth. The younger plants contain additional nutrients needed to fuel the geese’s molt and feather re-growth.

Migratory vs resident. Wild harbinger of seasons vs common nuisance. Even with Canada geese, nothing is just black or white.

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 exhibit: “Lake Alive!” opened May 1, 2015, and will remain open until March 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Canada geese have adapted well to living among humans, and some populations no longer migrate with the seasons. Photos by Larry Stone.

Canada geese have adapted well to living among humans, and some populations no longer migrate with the seasons. Photos by Larry Stone.

Snow Fleas

Late afternoon sunshine flooded through an aspen grove as we chugged up a hill on the Hartley Nature Center ski trails in Duluth. The warmth of a January thaw still hung in the air, and we paused to bask in the glow at the summit. A sprinkling of debris coated the surface of the softening snow. Suddenly one of the little specks vanished. Crouching down for a better look, I discovered that most of the sprinkles were tiny, leaping springtails known as snow fleas.

While springtails have six legs, they aren’t insects. Instead, they belong to the insects’ sister group with several different characteristics. A lack of wings, simple instead of compound eyes, differences in molting, a special mouthpart for drinking, and a hinged body part that can fling them into the air set springtails apart from true insects.

A springtail’s namesake spring is actually two modified legs on their final body segment, which form a forked appendage called a furcular. While resting, a springtail locks the prongs of its furcular up against its belly, thereby storing potential kinetic energy in its abdominal muscles. A rubber-like protein called resilin in the springtail’s exoskeleton helps to flex and store energy, too. The whole system is similar to an upside-down mouse trap.

When the springtail is startled by a potential predator, such as a giant human skier, it releases the clasp and the furcular snaps open against the ground. The critter launches into to the air, as far as 100 times its one-eighth of an inch body length. This erratic movement caused the mysterious, vanishing specks I noticed on the snow. After an uncontrolled flight, a springtail might land mere inches from its starting point, which is still far enough to fool many of its predators—like ants, beetles, and salamanders.

Post fling, springtails don’t always land on their feet. Luckily, they have a neat trick for righting themselves. Two inflatable grooming tools not only help them to keep clean, the sticky tubes can be adhered to the ground and used to pull the springtail upright.

While springtails are in the running to be the most abundant of all macroscopic animals (you might find 100,000 individuals in a square meter of soil, and there are about 3,600 species total), we typically only notice the one or two species who spend time on the surface of snow. Snow fleas get their name from their jumpy behavior and the substrate that makes them visible.

On balmy winter days, snow fleas scatter like pepper over the surface of the snowpack, or they might congregate in crawling hordes of a million individuals, drawn together by pheromones for mating party. It’s amazing that such a tiny thing can survive at all in the frozen expanse of snow. The magic that makes this possible is a unique protein especially rich in the amino acid glycine. This protein binds to ice crystals as they start to form, preventing them from growing larger, and so it acts as an antifreeze. The protein works down to about 21 degrees F, and at warmer temperatures it disappears! Doctors are studying its potential to help preserve human organs on their way to a transplant surgery.

Snow fleas don’t really spend much of their life on top of the snow. Like other springtails, they inhabit the soil and leaf litter. Other species of springtails (not snow fleas) live in tree canopies and even on top of water.  A moist environment is essential to prevent desiccation. Since they breathe directly through their skin (another difference from insects, who use a trachea), springtails must balance hydration with breathing. Complex structures on their skin trap tiny, durable reservoirs of air.

In their damp habitats, springtails are essential members of the community. What they lack in size, they make up for in numbers. They fragment organic material and make it easier for decomposers to break down. Springtails also curate the soil’s microbial inhabitants by eating bacteria and fungi, and by spreading them around. One common fungus—Laccaria bicolor—has turned the tables on springtails, though. This fungus paralyzes and decomposes the springtails, then sends their nitrogen over to a white pine through its roots.

On your next sunny adventure in the winter woods, be sure to keep an eye out for tiny, leaping specks on the snow. They just might be more interesting than you’d expect!

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 exhibit: “Lake Alive!” opened May 1, 2015, and will remain open until March 2016.

Find us on the web at www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.

Snow fleas are more interesting and important than their small size would indicate. Photo by Urmas Tartes.