Sunday, January 4, 2015

Woodpecker Niche

Just a few minutes up the trail after seeing the hairy woodpecker, we again heard a tapping noise through the fog and sleet. Like déjà vu, a black-and-white checkered woodpecker clung to a birch tree, using its chisel beak and kickstand tail to look for bugs along the knobby twigs. Only this time, there was no red on its head, the overall size was smaller, and her beak was tiny. Here was a downy woodpecker, the smaller cousin of the hairy woodpecker we had just seen.

Telling apart these two black-and-white woodpeckers is one of the rites of passage for beginning birders. My dad initiated me early, with this simple comparison: when you see a hairy woodpecker, you think “What a beak!” because it is so large (as long as the head). When you see a downy woodpecker, on the other hand, you might ask yourself “What beak?” because it is so tiny and inconspicuous.

To go with their smaller beaks, downy woodpeckers are only two-thirds the size of a hairy, and weigh only one third as much. This size difference has a big impact on the places that each woodpecker can forage, and allows them to exploit almost exactly the same range and habitats without too much direct competition for resources.

For example, the featherlight downy (who weighs under an ounce) gleans insects from bark crevices on smaller branches, and will often be seen dangling acrobatically on twigs like a chickadee. Meanwhile, the heavier hairy woodpeckers dig for wood-boring insects on trunks and large limbs that won’t swing under their weight.

Hairy woodpeckers also specialize by following pileated woodpeckers. After a pileated excavates a large hole and moves on, a hairy might clean up the crumbs of insects that the pileated missed. Hairy woodpeckers have also been seen drilling sap wells into sugar cane, and nabbing sap from wells made by yellow-bellied sapsuckers.

Downy woodpeckers have their own set of special feeding habits. Their small body and sharp beak make it easy for them to cling to the dried stalk of a goldenrod plant and drill precisely into a gall on the stem. Inside, they might find a sweet, juicy gall fly larvae for dinner. Downies compete with chickadees for this food source. If you find a bird-eaten gall, you can guess at the culprit by the neatness of the hole. Chickadees have much blunter beaks and excavate a messy, wide-angled hole.

When downy woodpeckers forage on trunks, as the females are more likely to do in the winter, they are better able to move horizontally and downward. This might give them a different angle on the bark crevices, and a better view of food that larger species missed.

Angles are important for their nest sites, too. Hairy and downy woodpeckers both choose a trunk or branch that is leaning to one side, and chisel the nest entrance into the underside. Scientists hypothesize that this keeps flying squirrels or sapsuckers from moving in. Both hairies and downies prefer excavating their nest holes in a living tree with a rotted core, or a soft dead tree, although the downy can use smaller trees and limbs.

The slight but important differences between hairy and downy woodpeckers that allow them to share a forest without pushing each other out are a function of their ecological niches. In shorthand, we sometimes define “niche” as “how an organism makes a living.” More technically, a niche can be defined as “the sum of the habitat requirements (including both the living and non-living elements of the environment) that allow a species to persist and produce offspring.” A niche also includes the ways that an organism responds to the distribution of resources, and to competition from other species.

All species have a niche. As we hiked across a snowmobile trail on the way back to our car, it struck me that human adventurers fulfill more than just one niche, too. With trails for skiing, skijoring, snowmobiling, hiking, and fat biking winding through our forests, everyone can get out and enjoy the woods in their own favorite way. What will you do?

If snowshoeing fits your niche, then join me on a snowshoe and tracking adventure this winter! Find the dates, descriptions, and registration instructions at

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,

Friday, December 26, 2014

Hairy Woodpecker in the Fog

Perpetual twilight cloaked the forest on the darkest day of the year. Even at noon, fog hung densely between us and the sun. Cabin fever had set in, and we felt like banging our heads against a wall. Trying to make the best of it, we layered up and ventured out onto the Superior Hiking Trail. The elegant forms of birch, aspen, oak, and balsam fir near the trail stood out against a plain background. Beyond them, only the gray mist met our eyes. Nothing moved in the oppressive dampness, save us and the assortment of snow, sleet, and rain drops that pelted the world.

Then a bird swooped through the edge of our vision, and a tapping sound punctuated the constant hiss of sleet. High on the trunk of a dying birch, a black-and-white-checkered woodpecker foraged in the bark crevices. His feathers blended perfectly with the white bark and black gnarls. A substantial, chisel-like beak – as long as the profile of his head – was evidently the perfect tool for prying and pecking bark beetle larvae from out of the punky wood. While leaning back for a better look, or perhaps winding up for a swing at the tree, his stiff tail provided a kickstand for support. The small patch of red feathers on the back of his head was a welcome bit of color in the gray woods, and it also informed me of his proper pronoun.

We didn’t stop to watch this male hairy woodpecker, but I did mull over the state of his head as we hiked on. He’s obviously quite well adapted for his lifestyle, but how can that little bird bang his head against trees all day and not develop debilitating headaches?  Scientists have been studying this problem for years, and for good reason. If we could figure out how to engineer anti-shock mechanisms into rapid collisions so that they were less damaging, it would revolutionize the world of transportation safety.

In the case of the woodpecker, scientists in China used CT scans and computer models to discover that the impact energy is converted to strain energy, and 99.7% of the strain energy is dissipated throughout the woodpecker’s body. The 0.3% of the strain energy that affects the head is converted to heat energy. This could cause the woodpecker’s brain to overheat and result in a different kind of damage, which is why woodpeckers take frequent breaks while they are pecking. It isn’t just about perfecting a rhythm or grabbing a bug, they are protecting their brain.

My psyche could use similar protection from the strain brought on by soupy weather and cabin fever! Instead of taking out our frustration by punching the walls, we hiked faster into the sleet. As the strain dissipated as heat, our red cheeks brought a little more cheer into the fog. It will only get brighter from here. Happy Solstice!

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,

Friday, December 19, 2014

Winter House Guests

The pile of sweaty skiing and outdoor clothes in my closet had begun to smell a little rank, as polypro is inclined to do. So I hoisted the laundry basket and schlepped it down two flights of stairs. In the corner of the last step, something small and dark, about the size of a nickel, caught my eye. “Thunk” went the laundry as I crouched down to get a better look. Sure enough, a brown spider crouched among the dust bunnies and dog hairs.

Now, I know that this type of discovery elicits a wide variety of responses in people, and the majority probably lean toward some combo of screaming and smashing. But I’m at the other end of the spectrum. It’s been hard to “see” nature lately, since I spend most daylight hours in the office. As a result, I’ve been feeling a little deprived of my usual encounters with wildlife, so I felt honored to have some nature living in my stairwell. I ran up the steps, grabbed my camera, and did a little wildlife photography there on the basement steps.

Long, hairy, rusty brown legs were banded with darker stripes. Her oval-shaped abdomen was tan, with a squiggly black chevron pattern and more hair. Long, slender pedipalps (also hairy), stood ready on either side of her mouth to taste, smell, and or help crush her food. Indeed, it was the delicacy of the pedipalps that identified her as a female – a male would have big club-like pedipalps to aid in reproduction.

A quick search through Larry Weber’s Spiders of the Northwoods just got me more confused on the identity of the little critter. Show me some tree buds and I’ll point out minute differences that indicate this twig is (obviously) from a beaked hazel and the other one is from an American hazel. Show me a spider, and I say, well, it has long legs and dark stripes. That describes at least a third of the spiders in my guide.

For help, I went straight to the source and emailed the photo to Larry. With enthusiasm, he identified is as “a type of Funnel-web Spider (Funnel-weaver); family Agelenidae. She appears to be the genus Tegenaria.” Then—as with any new roommate—I Googled her to find out more.

According to Wikipedia (a good place to start, but not the final word), “house spiders of the genus Tegenaria are fast-running brownish funnel-web weavers that occupy much of the Northern Hemisphere except for Japan and Indonesia.” In northwestern Europe, where giant house spiders (Tegenaria duellica) are native, the British affectionately call them “dust bunny spiders,” due to their propensity to set up a territory under furniture.

Long ago, these spiders might also have chosen to set up territories on the ships carrying the first European settlers in the 1600s, and/or in shipments of British lumber during the Napoleonic Wars (early 1800s), thus spreading from Europe to America. Their close association with humans may have earned them passage elsewhere, too, and they are now suspected to live in almost every country on Earth.

You have to be fast to colonize the world, and giant house spiders held the held the Guinness Book of World Records for top spider speed (1.18 mph) until 1987. The “spiders” that beat their record are not even true spiders! Hmph!

Happily, most of these house spiders would rather try to escape than try to bite you or your pet, so they pose little danger as roommates. David Sedaris, bestselling humorist and author, once befriended a number of Tegenaria spiders and noted that they are “as quiet and unobtrusive as Amish farmers.” One thing I did worry about was where this spider was living. Oh, I don’t care if it sets up shop in the basement stairwell—that wasn’t the problem. But everything I read suggested that these Funnel-web spiders should be living on a flat, sheet-like web with a tubular retreat at one corner. Nowhere at the bottom of the stairs could I find such a web. So I ventured into the basement itself to see if I could find the spider’s true home.

I found the nooks and crannies surprisingly clear of webs, until I reached the farthest back corner. There, above the phone and internet boxes, hung a beautiful gossamer sheet web. Tentative jiggling it, I was surprised by a tiny black spider that suddenly bungee—jumped into the abyss and then lowered himself (male spiders are smaller) smoothly on a line of silk. A second black spider still clung to the web. As I looked even closer, I noticed several pale, leggy cellar spiders clinging upside down to messy, irregular webs like something out of Tim Burton's The Nightmare Before Christmas.

The crumpled bodies of dead insects littered the floor under this spider colony. I took this as evidence that these spiders were contributing members of the household, not just some lazy freeloaders. Through all this adventure, my dirty clothes sat abandoned on the floor. If only spiders could add “doing laundry” to their list of helpful talents!   

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,

Friday, December 12, 2014

Spinus pinus

Maybe you’ve seen them, too: flocks of brownish birds recklessly swarming on the sandy shoulders and even the traveled lanes of snowy roads. They don’t move until the last possible second, and sometimes that’s too late.

At the Museum, we’ve been debating their identity. I’ve seen flocks of snow buntings lately, but those are black and white. Last week, Jayme Morey, Collections Assistant at the Museum, decided that the solution to our curiosity was to bring in one of the slowpokes off the side of the road to get a better look. With the help of Diane Kraemer, our other Collections Assistant, she identified the tiny, five-inch long corpse as a pine siskin, Spinus pinus.

Despite their lack of even a four-year-old’s understanding of traffic safety, pine siskins have some amazing strategies for winter survival. And because they normally live in the remote forests of Canada, you can’t blame them for being naïve about cars. These little finches do have powerful engines, though. They can survive negative 94 degree Fahrenheit nights by revving up their metabolic rate to five times normal for several hours. That’s 40% higher than other “normal” songbirds.

In order to fuel those internal fires, pine siskins put on 50% more winter fat than their cousins—common redpolls and American goldfinches. They also store a bedtime snack right in their esophagus—in the expandable section called the “crop.” But it isn’t just a single cookie and glass of milk; their crop can store seeds equal to 10% of their body mass. Those calories could get them through five or six hours of sub-zero temperatures.

Having enough fuel to fill their crops and fuel their engines is the key to survival for pine siskins. That is what brought them south, to Northern Wisconsin. In the face of winter and diminished food supplies, every animal must choose between three basic survival strategies: hibernate, migrate, or stay active. Pine siskins have adapted to migrate, but not in the regular, biannual travels between particular places like common loons. Pine siskins “irrupt” in irregular migrations every couple years to wherever the food supply is greatest.

When their typical winter food supplies in Canada are low, pine siskins may flock into New England, the upper Midwest, or even the southeastern United States. They are looking for plentiful supplies of seeds from pines, cedars, larch, hemlock, spruce, alder, birch, and maple. This year, I’ve seen lots of hemlock cone scales littering the snow. This tells me that there’s a good crop of hemlock cones, and that many critters are taking advantage of the bounty.

Just as the boom and bust cycles of acorns kept passenger pigeons on the move and allowed some oaks to sprout, the cycles of conifer seed scarcity in Canada may disperse siskins and reduce the birds’ long-term impact on the plants.

Pine siskins’ irruptive behavior also brings a diversion from our regular winter birds. With a touch of yellow on their wings, pine siskins look a bit like goldfinches, but they are heavily streaked on their head and body, while goldfinches have smoother colors. At your feeders, pine siskins prefer smaller seeds without tough shells, like thistle and oil sunflower.

Be sure to watch for sick birds at your feeders. The high concentrations of birds in an irruption year can help spread Salmonella bacteria. Sick birds will look thin, fluffed up, and often have swollen eyelids. If you see this, clean your feeders thoroughly (with care to protect yourself) and take them down for a week to allow large flocks with sick birds to disperse.

In the woods, listen for siskins’ wheezy contact calls, and look for their undulating flight. Flocks will often feed gregariously, and then swoop off one-by-one to the next tree. It can be hard to get a good look while they are flitting about in the tippy top of trees, in the high branches where cones are most plentiful. Still, you can admire their acrobatics as they cling upside down to bouncing branch tips.

On the road, watch out! Pine siskins are fond of minerals like road salt. So, the next time you tap your brakes for a flock of brownish birds recklessly swarming on the traveled lanes of an snowy road, at least you’ll know what you’re dodging, and perhaps give a little more credit (and space) to your fellow winter travelers.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,

Friday, December 5, 2014

Where are the loons?

Temperatures plummeted beneath a black dome of sparking stars. As the eight inches of ice already on the lake thickened and expanded in the cold, it sang the eerie notes of winter. A couple weeks ago the ice-notes were high and squeaky – shorter frequencies due to thinner ice – but tonight they deepened into the lower moans of thick ice. The ice’s plaintive wails brought to mind the lake songs of summer – as performed by loons.

All summer long we alternately curse and acclaim their calls. One grumpy (and tired) visitor asked me “Do loons ever sleep?” after nearby birds had caterwauled into the wee hours of the morning. Although they do sleep, it’s not on our schedule. Since loons are visual hunters, they must feed when sunlight penetrates into fish habitat. When darkness brings relative quiet to the woods, they use that opportunity to communicate with neighbors. 

“Who’s there? I’m here,” may be the basic message in their wail. By speaking up, each loon reasserts that it is on its territory, and ready to defend against invaders. If a loon remains quiet, that could signal that its territory is free for the taking, a risky message to convey. As male loons patrol their territory boundaries each night, encountering a another male intruder will trigger a yodeling contest. That’s the maniacal cry, called “the laugh of the deeply insane” by writer John McPhee, that you curse might at 3:00 a.m. It may or may not result in a physical battle.

Where are the loons now, though? I haven’t heard them calling since late summer, or seen an adult in quite a while. The last loon I saw was the sole surviving juvenile from a nest in a nearby bay. With any luck, he was able to gain enough strength to migrate south by November 14, when the lake started to freeze.

There’s no way of knowing where my particular unmarked loon neighbor went, but the United States Geological Survey (USGS) has captured and radiomarked several juvenile loons on lakes scattered across Minnesota and Wisconsin. Researchers use geolocators and satellite transmitters to track the movements of migrating and wintering loons. From their data, we can watch the juvenile loons move south in almost real-time, on animated maps.

As with most years, the 2014 juveniles began their journeys from late October to mid-November. It looks like a few loons headed south just ahead of ice-up! Their routes aren’t identical, but some juvenile loons made a layover on Lake Michigan. Others made pit stops on the Mississippi River or reservoirs in the central states. The juveniles must make the trip alone, since their parents and non-breeding adults migrate earlier. In general, non-breeding adults start migration in late August, mothers leave in September, and fathers head out in October.

The ultimate destination for many of our Wisconsin and Minnesota loons is the Gulf of Mexico, and specifically the west coast of Florida. Their main habitat requirements are plenty of fish to eat and clear water to hunt in. Southern inland lakes tend to have warm, shallow, murky water, and alligators (!), so the ocean provides a better option. There, loons face the challenge of transitioning from freshwater to saltwater. They’ve adapted by excreting salt out of glands in their skull between their eyes. The glands drip almost constantly during the winter…sort of like how my nose adapts to winter, too…

After making the big journey and coping with salt, loons gain access to a seafood feast. Wintering loons eat flounder, crabs, lobster, shrimp, gulf menhaden, bay anchovies, silversides, and more. The ocean bounty gives loons enough energy to molt and regrow all of their feathers, but danger is still present. Not much is known about loon predation in the ocean, but I’ve heard that dog sharks will race upward through the water to attack loons from below.

Unfortunately for human snowbirds, the loons’ winter feast doesn’t happen within viewing distance. Most loons spend the winter at least five miles (and often much farther) offshore. Even if you could see the loons, you might not recognize them. The adults and juveniles all wear drab brown plumage, and sport dark eyes instead of the ruby red eyes of breeding season. They aren’t known to vocalize. In the spring, adults molt back into breeding plumage, complete with red eye. Juveniles stay brown and ocean-bound while they mature, and will only migrate back toward their natal lake after they are three to four years old.

Loons need to winter on the ocean, but I am grateful that human adaptations allow me to enjoy my northern lakes all year round. When the haunting calls of the loons fade with the summer sunshine, the lake itself sings an icy winter tune. Perhaps it, too, is asking “Where are the loons?”

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,

Friday, November 28, 2014

A Natural History of Thanksgiving Dinner

The Thanksgiving dinner menu is often pretty standard. When you’re feeding a large group of people with picky kids (and adults) to satisfy, and traditions to uphold, it doesn’t pay to get crazy. You can’t go wrong with  turkey, green beans, potatoes, cranberry sauce, and pumpkin. But have you ever thought about what those foods are like before they get to your table? You may have given thanks for the bounty, and perhaps even for the Earth that provided them. But do you think about how and where they’ve grown in the dirt, under the hot sun, for thousands of years? Or  the odd adaptations that keep them alive? Maybe  your “normal” Thanksgiving dinner is pretty extraordinary.

Let’s start at the end, with pumpkin pie. If you’re ambitious, you may have  baked a pumpkin and scooped the soft, orange flesh out of the rind. Although I enjoy pumpkin pie, I’ve often thought it a little weird to take a vegetable, mix it with sugar and eggs, and make a dessert. Personally, I prefer a berry pie.

But, to  a botanist, a pumpkin is a berry! Scientifically speaking, a berry is a fleshy fruit produced from a single flower. Pumpkins are a  type of thick-walled berry known as a pepo. Appropriately, the scientific name for the pumpkin is Cucurbita pepo. C. pepo is also the name for the acorn squash, delicata squash, spaghetti squash, pattypan squash, zucchini, and ornamental gourds. Despite the fact that some on the list are hard-skinned winter squash, and some are soft and juicy summer squash, they are all fruits of the same species of plant.

That plant was domesticated from its wild ancestors about 10,000 years ago. We know this from the large seeds—characteristic of C. pepo, but not it wild cousins—that were unearthed in a cave in Oaxaca, Mexico, and dated using carbon-14. That makes pumpkins and their cousins the oldest known domesticated plants in the Americas.

While the beans in your green bean casserole aren’t quite that old, they are one of the longest-cultivated plants in the Americas. Kidney, black, pinto, and navy beans all were domesticated in South America. As with pumpkins, many types of beans all belong to the same species: Phaseolus vulgaris (vulgaris means common). Green beans are simply the unripe fruit of various cultivars of the common bean -- selected especially for the fleshiness, flavor, or sweetness of their pods.

Long before humans domesticated beans, the beans developed their own beneficial relationship with another organism. Through a series of chemical signals, soil bacteria called rhizobia trigger the bean plant to grow deformed root hairs that expand into nodules. The bacteria waltz on in, becoming guests in the bean plant’s spare room. While the bean feeds the rhizobia with carbohydrates, proteins, and even oxygen, rhizobia are not moochers. The bacteria possess the rare talent of taking nitrogen out of the air, and fixing it into a form that the beans can use.

This special relationship between the beans and the bacteria impacts our relationship with beans, too. Nitrogen is a basic building block of amino acids, and amino acids are the basic building blocks for protein. The mutualistic symbiosis that beans have with rhizobia give the beans the high protein content we desire.

The bean plants themselves also make pretty good houseguests. Microscopic hairs on their leaves can be used to trap bedbugs!

Leaves from the potato plant are also bad for bugs. All parts of the potato plant – except for the tuber itself – contain toxic alkaloids like solanine that are supposed to protect the plant from its predators.

Human predators–hunters--are one of the biggest causes of mortality for the Thanksgiving centerpiece. Hunters are responsible for two thirds of the mortality in tom turkeys. Of course, you probably weren’t eating a wild turkey. But if you were, could you have figured out how good his genes were, and if he had intestinal parasites or not? The hens could have!

Turns out, it’s all in the snood. This fleshy outgrowth hangs down over the male’s beak and is used to dissipate heat when he’s strutting his stuff. A longer snood also signals to the ladies that he has good genes that are helping him ward off intestinal parasites. What a life!

All of the dishes on our Thanksgiving table were made from living things. But before they went into the pot, they had lives filled with history, drama, stress, and relationships not so unlike ours. And now, their lives are part of ours, sustaining us with vital products created in their very own bodies. “How calmly, as though it were an ordinary thing, we eat the blessed earth.” -- Mary Oliver.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,

Friday, November 21, 2014

Little Kings of the Winter Woods

A light wind rattled the oak leaves still clinging to their twigs, while my snowshoes crunched through the crust, and expanding lake ice sang eerily in the distance. So far my walk – a quest for inspiration – had yielded only cold cheeks and a stark winter woods.

Near the end of the trail, a new sound filtered gradually into my consciousness. High, thin, “see see” notes drifted down from the dense foliage of a little stand of fir trees. Chickadees! I thought at first, and smiled, although I did not look up. Then I caught a movement out of the corner of my eye. Just above my head, several little birds fluttered in the boughs. The seemed too delicate to be chickadees, their song really was too high and thin, so now I focused in on their field marks.

Instead of the black chin of a chickadee, I looked up at a creamy-colored throat and breast. Their backs and wings were warm olive with black and yellow markings. I started to develop a hunch for who might be in this little flock, but it took me several minutes of focused observation (of course I’d forgotten to carry binoculars) before one tipped her little head right toward me. Ah ha! A yellow stripe ran down the top of her head, black stripes surrounded it, with another black stripe through the eyes. Golden-crowned kinglet.

Now here was some inspiration. Golden-crowned kinglets are one of the smallest songbirds, and yet they commonly overwinter in places where the nighttime lows plummet to -40 degrees Fahrenheit. Bernd Heinrich, a professor of mine from the University of Vermont, wrote about them extensively in his book “Winter World.” He mused, “Only if I knew how and why a golden-crowned kinglet survives a Maine or Alaskan [or Wisconsin!] winter would I understand the story of winter survival…The kinglet is thus iconic not only of winter, but also of adaptability under adverse conditions.”

I inhaled deeply, a breath of gratitude and wonder at coming across these little miracles of adaptation, but the dry, 11 degree air caught painfully in my lungs. The kinglets showed no such distress despite their acrobatic and aerobic exercise. Not only are their bird lungs quite different from mine, each of their delicate nostrils is covered by a single, tiny feather. I can only lament that I didn’t wear a scarf.

Crunching around to get a better look at the flock, my snowshoes caught awkwardly on twigs and crust. Help as they do, snowshoes can’t quite float my large mammal body on top of the drifts. From my new vantage, though, I got a great look at one of the flock fluttering in mid-air. He could actually hover under the twig to feed, just like a hummingbird. Then with an effortless swoop, he landed on the very tip of a different twig, his two-penny weight barely bending the tree as he dipped his head in continuous feeding motions.

Kinglets need to feed constantly, at almost one peck per second, discovered Bernd. Why this apparent gluttony? In order to maintain their internal furnace at 110 degrees Fahrenheit, kinglets need to eat the 2-to-3 times their own bodyweight of energy dense food each short winter day.

What could kinglets possibly be finding to eat in this barren landscape? Bernd wondered that, too. His research included dissecting a kinglet to examine the gizzard contents—inchworms—then examining the trees themselves to find living examples of those same inchworms, and finally raising the inchworms to adulthood so that they could be identified. The answer: kinglets often eat caterpillars of the one-spotted variant moth (Hypagyrtis unipunctata). These just happen to be relatives of the Bruce spanworm moths I encountered recently, and I can’t help but wonder if the spanworm moths or their eggs might also be food for winter kinglets.

The slight breeze cut through even my puffy winter coat. How are those tiny birds staying warm? Kinglets don’t have a big enough body to store fat like a bear does, but they do grow more feathers each autumn. During the winter, feathers make up 8% of their body weight. Artic explorers wear about the same relative weight of clothing. Just like my jacket, those feathers are great insulation.

But their feet aren’t feathered, I noted, wiggling my warm toes inside wool socks and thick boots. And that is where any desire I might have to be a kinglet stops. Their feet are always cold. It isn’t worth the effort to keep them warm, as long as they aren’t frozen and damaged. The real worry is that cold blood returning to the body from the feet might lower their core temperature. The solution is a counter-current heat exchange system, where arteries with warm blood from the body passively warm up blood from the feet before it re-enters the body.

This evening the kinglets will continue with their constant search for food. They’ll feed until the last instant before dark, then crowd into whatever shelter they can find, and huddle up with the flock. Those are their instructions for life. Amazing, perhaps, but not right for me. I prefer Mary Oliver’s “Instructions for living a life. Pay attention. Be astonished. Tell about it.”  And thanks to the kinglets, I had something to tell you about today.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! The current exhibit, “Nature’s Superheroes—Adventures with Adaptations,” opens in May 2014 and will remain open until March 2015.

Find us on the web at to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot,