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

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

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 na├»ve 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 www.cablemuseum.org to learn more about our exhibits and programs. Discover us on Facebook, or at our blogspot, http://cablemuseumnaturalconnections.blogspot.com.


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


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


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


Friday, November 14, 2014

Passenger Pigeons and Lyme

Today my roof is buried under more than a foot of snow, and the drift is sliding off of the high-angle metal in a slow-motion avalanche. Not long ago, my roof hosted an avalanche of a very different kind – an avalanche of acorns.

Back in August, I started hearing weird noises on the roof. A loud plunk would be followed by a series of rattles, then silence, and sometimes a final plink. While working in the garden one afternoon, I figured it out. The noises started, the short silence ensued, and an acorn launched off the roof, sailed over my head and plinked on the roof of my car. Every slight breeze brought the same series of events hailing down on me from the large oak in the yard. The driveway soon became a roly-poly mess of round, brown nuts.

Oaks are mast trees, which means that they save up their energy for three to five years before producing thousands of acorns all at once. And single trees don’t usually mast on their own. Somehow, all the trees in an area communicate to determine which year will be the right one. “In the old time, our elders say, the trees talked to each other,” writes Robin Wall Kimmerer in her book Braiding Sweetgrass.

Scientists don’t go for that explanation. Foresters hypothesize that trees simply wait until they’ve built up enough energy. But that doesn’t explain how trees in rich and poor habitats are ready at the same time. Mycologists now theorize that the networks of mycorrhizal fungi that connect a forest by the roots may be the agent of coordination. “A kind of Robin Hood,” writes Kimmerer, “they take from the rich and give to the poor, so that all the trees arrive at the same carbon surplus at the same time…Through unity, survival. All flourishing is mutual.”

Why does masting together equal flourishing? It is simple math. With thousands of acorns available at once, the hordes of acorn-eating seed predators cannot possibly eat them all. Some, at least, will survive to grow a new tree.

At least, that is how it works today. In the past, there was a seed predator that could clean out an oak forest, even in a mast year. Passenger pigeons, once the most numerous land bird on the continent, traveled in flocks of millions. When they descended on a grove of oaks, the twigs, branches, and even whole trees broke under the weight of their bodies. By one report, not an acorn could be found after they moved on.

Their nesting colonies, by necessity, also followed the mast. The largest nesting area ever recorded was in central Wisconsin in 1871. The size was estimated at 850 square miles. The population was estimated at 136,000,000 birds. It takes a lot of food to support that many birds, even for the two months or less it took to mate, brood, and fledge the squabs.

Now that passenger pigeons are extinct (the last one died 100 years ago this fall), it’s difficult to tease out the significance of their lives, and the consequences of their demise.

What we do know is the impact that extra acorns (presumably the ones no longer eaten by flocks of pigeons) have on several other species. In New York, scientists have shown that Lyme disease increases two years after an acorn mast year. The mechanism seems to be the increase in white-tailed deer numbers and local density, along with an increase in the population of mice (one of the best carriers of the Lyme-causing bacterium).

Deer help the ticks reproduce. Mice infect the ticks with Lyme disease. The ticks infect us. If the pigeons were still here to eat all the nuts, and prevent the local concentrations of deer, mice, and infected ticks, hypothesizes ornithologist David Blockstein, would that also keep the spread of Lyme disease in check?

The world is a complicated place, and we can never fully predict the consequences of our actions. None of the nineteenth century market hunters--who slaughtered thousands of passenger pigeons per day with the conviction that they would always be plentiful—would have ever suspected that their actions might result in their descendants suffering from a tick-borne disease.

Jerry Niemi, from the Natural Resources Research Institute, at the University of Minnesota, Duluth, recently spoke on the rise and fall of bird populations in Minnesota and Wisconsin. Since the year 1600, he recounted, 131 species of birds have become extinct. Today, another 1213 species are facing the threat of extinction. That is 12% of all known species of birds. What cascade of events will their losses trigger? What kind of avalanche will climate change bring? Certainly not one as quaint and harmless as acorns or snow tumbling off my roof.

Kimmerer’s wisdom sums it up for me: “What happens to one, happens to us all. We can starve together or feast together. All flourishing is mutual.”

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

Friday, November 7, 2014

Five things that improve after a hard freeze:

1. Sparkling rubies nestle in emerald green moss, illuminated by the weak glow of a headlamp. Dampness oozes from the deep layers of peat soil, and from the fresh layers of sphagnum that climb the scaffolding of twiggy leatherleaf bushes. And my boots. The dampness also oozes around my boots.

Reaching, stretching, I search almost manically for the little bog jewels. Ignoring back aches, ignoring the way that damp moss and damp breeze suck the warmth from fingertips, ignoring a friend who is not ignoring those things and wants to go home. The one quart yogurt tub in my left hand has almost been filled with cranberries by my right hand. Almost. Not quite, and look, there’s another patch by that hummock.  And another over there. That one is pale and firm--not yet frosted and sweetened. Look! Three perfect jewels dangle among dry threads of grass.

The first (or second?) wet snowstorm of fall had pushed marble-size berries deep into the moss. Then it melted. More snow is forecast, so we must pick everything we want now, under the cloudy darkness, listening to the rush of city traffic not far beyond the soggy bog and tangled forest.

A cherry red gem gleams from its cozy bed. I pluck it with numb fingers; listen to it plunk onto its comrades. In its hole, I spy more red. I scoop that one up too, only to see a third fruit shining from even deeper. This one is so perfectly ripe that I place it on my tongue, gently pressing it against the roof of my mouth until it bursts. No one sees my pucker face in the dark. Nor do they hear the involuntary hum of satisfaction as the frost-softened, cold-sweetened, pungently wild flavor of the bog fills my night.



2. The hard edge of my library card peels elegant curls of frost off the windshield. A quick peek under the garden cold frame reveals a small grove of deep green spinach–frozen solid. Oh well; next year I’ll eat them sooner. But hard frosts require a clear sky, and the day soon warms. Later, I find my spinach cheerful, thawed, sprightly and intact. Into the salad bowl, quick, before it’s too late! Unlike the wilted and bitter salads of summer, these leaves are sturdy and sweet, requiring much grateful mastication in my sunny kitchen.

3. A friend tells me that his delivery guy drove through a sideways storm. It’s gone now, but the northwest sides of the tree trunks are white—skunk striped with damp, driven flakes. Our hiking boots make sculpted designs in the snow. The woods are silent and still. We see only red squirrels and one hairy woodpecker. But others have been here recently. Otters, fishers, foxes, voles, and shrews crossed our path. The snow holds the record of their presence and their passing. Otherwise, how would I know? Snow makes the forest feel alive.

4. In the sunny opening created by a fallen sugar maple, little tan moths flutter feebly. Moths? But it can’t be more than forty degrees. Quick! Get a photo! Here, I caught one. Delicate fringes outline their wings, while darker brown, fuzzy, scalloped lines fill them in. They are everywhere. On the snow. Deeper in the woods. Drifting in front of our noses.

Bruce spanworms are pesky little green and yellow inchworms that turn unfurling spring leaves into lacy green skeletons. They prefer sugar maple, aspen, elm, and apple. In June, they pupate, and wait until cold drives away hungry bats, birds, and predacious insects. In the relative safety of the late-fall woods, the adults emerge. Wingless females, full of eggs instead of flight muscles, simply crawl up the nearest tree to waft pheromones into the breeze. They wait. Meanwhile, the males give thanks for antifreeze, and shiver large flight muscles up to temperature. The cold dictates relatively slow wing beats, but those wings are broad enough to carry a lightweight body through the air. Females lay pale green eggs into the grooves of bark. Neither adult eats. Over winter, the eggs turn orange. Unfazed by the cold, the caterpillars hatch in May.


5. Mosquitoes. My deepest gratitude to whichever source of infinite wisdom reserved the power of winter flight for soft-winged moths, and not mosquitoes. Praise be to the hard freeze. Praise be to the delicacy of their little, buzzing lives.

Friday, October 31, 2014

Lingering in Happiness

We turned our faces toward the bluebird sky, closed eyelids against the brilliant sun, and soaked up its mid-afternoon warmth. Although the day was not especially warm, the whisper of a breeze let us keep every ray of the sun and every bit of heat we’d generated on a little walk. Knowing that we won’t get many more days like this before snow flies and temperatures plummet, my parents and I basked like turtles on that fallen log–lingering in happiness.

Recently I had another encounter with happiness: not only from being in a group of wonderful people, but also discussing how to measure happiness across an entire nation. Jack and Mary Wichita, local Museum members, spoke about a trip to Bhutan, and the “Land of the Thunder Dragon’s” Gross National Happiness Index.

As a small country of 750,000 people in Southern Asian, Bhutan seems fairly unremarkable. But in the 1970s, His Majesty the Fourth King of Bhutan, Jigme Singye Wangchuck, coined the term “Gross National Happiness.” He started governing on the concept that “…sustainable development should take a holistic approach towards notions of progress and give equal importance to non-economic aspects of wellbeing.”

As globalization, economic development, and television threaten their traditional way of life, the Bhutanese are making decisions with more than just money and “things” in mind. The values that contribute to happiness – actually measured in “sufficiency” – are presented as nine domains: psychological wellbeing, health, education, time use, cultural diversity and resilience, good governance, community vitality, ecological diversity and resilience, and living standards. If you were “sufficient” in all of those domains, wouldn’t you be happy?

Jack and Mary highlighted some of the practical applications of these values that relate to the environment. The constitution of Bhutan says all citizens have a duty to prevent pollution. Organic is farming mandated by law, and chemical fertilizers and pesticides are banned. The country is 70% forested, and their policy dictates that it not fall below 60%. The export of lumber is prohibited.

Bhutan wishes to stay carbon neutral (plentiful electricity comes from hydroelectric dams), so citizens must apply to get one of the limited number of permits to own an automobile. As a result, traffic is light, smog doesn’t build up, and people stay healthy by walking.

Historically, walking has been the main of transportation in Bhutan, so access to health care is measured by walking time. Their goal is for each person to live within an hour walk to a clinic. Do you even have that level of convenience?

Bhutanese also promote health through value placed on getting sufficient sleep, which falls under the “time use” domain. (I’d love to have more cultural support for getting enough sleep…but how can I sleep with ideas like these dancing around in my head?)

What if our country--or even our hometown--governed based on these values? I’m already surrounded by people who strive to drive less, walk more, garden organically, and conserve resources. We’ve all experienced the ability of exercise, sleep, and time in nature to increase happiness. How can we promote these values even more?

Many studies have shown how nature can increase our happiness, and I’ve written about them here before. A common soil bacteria – Mycobacterium vaccae – has been shown to increase serotonin (the “happy” hormone) levels in mice. Even the nature within our bodies –bacteria in our guts – regulates serotonin levels. Vitamin D, synthesized with help from the sun, can help prevent depression. “Forest bathing” is a recognized relaxation and stress management activity in Japan.

As these ideas swirled in my head, I kept landing on the title of one of my favorite Mary Oliver poems: “Lingering in Happiness.” Lovely and short, I once had it memorized for easy access. It begins: “After rain, after many days without rain…” and then describes the dampness trickling down through the forest, permeating the soil, feeding the “roots of the oaks”, until even the stones “feel themselves being touched.”

Like raindrops that touch every bit of life in the forest, like the sunshine that soaked through our eyelids as we sat on the fallen log, like the conservation values that permeate life in Bhutan, I believe our happiness is inseparable from our relationship with the earth. Perhaps we should go outside--right now!--and find a forest where we, too, can linger in happiness.

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


Friday, October 24, 2014

Blue Jays

Crinkly brown oak leaves danced across the path. My bike tires swished satisfyingly through drifts of leaves on the ground. Up ahead, a small flock of blue jays swooped across the road one at a time, perfectly complementing the brilliant blue sky. After landing safely in the brush, they cried a harsh “Jay! Jay! Jay!” in alarm at my approach.

Cheerful feeder friend, or wily villain? These big, noisy, gregarious songbirds have quite a varied reputation. But historic accounts of their villainy—like John James Audubon’s painting of three blue jays sucking another birds’ eggs, and his accompanying quote: “Who could imagine that selfishness, duplicity, and malice should form the moral accompaniments of so much physical perfection!"—are now known to be overblown.

While blue jays may occasionally raid the nests of other birds for eggs and nestlings, one study examined the stomachs of 530 blue jays and found traces of eggs and nestlings in only 6.  That’s 1.1%. It seems that other species fared quite a bit better than those 530 blue jays.

Even when blue jays eat such non-endearing foods as sunflower seeds and cracked corn, they can get a bad reputation for bullying and gluttony at the bird feeder. By imitating the scream of a red-tailed hawk or red-shouldered hawk as it approaches a food source, a blue jay can scare off other birds and hog the food. For a while. It seems that the other birds figure it out pretty quickly and return to feed.

In some cases, though, the blue jays’ raptor imitations and alarm calls may indicate that a predator is nearby--very kindly warning all the species in the area about shared danger. Plus, having a big, brightly-colored bird with a moveable crest at the feeder was super exciting when teaching my toddler nephews about birds. They learned pretty quickly to identify “downy, gol-fin, jun-co,” and several others while I held them up to see the birdfeeder. But no other bird elicited the childish excitement of “bu-jay!”

I didn’t confuse the toddlers by telling them that blue jays don’t truly have blue feathers. If you hold a feather from a blue jay, bluebird, or indigo bunting in front of a light, it looks brown. This is caused by melanin, a pigment that also makes feathers stronger and more resistant to wear. The blue is really structural color.

The tiny barbs on blue jays’ feathers are actually made of three layers. Light passes easily through a transparent outer layer into box cells. As the feather was growing, thread-like keratin molecules in the box cells separated from liquid. When the cells died, the liquid was replaced by air and the box cells remained filled with a structure of keratin cells and air pockets. This structure causes the red and yellow wavelengths of incoming light to interfere and cancel each other out.

Blue wavelengths are amplified and reflected back to your eye. Small differences in the keratin patterns result in different shades of blue. In some parrots, yellow pigment overlies the blue-ing structures and creates green.

A layer of dark cells filled with the pigment melanin underlies the box cells. These dark cells enhance the blues we see, and also create the striking black patterns on jays’ faces that may help them recognize each other. What’s even more amazing is that the precise nanostructures that allow for blue birds have evolved independently in many unrelated species. Also, this is the same basic science of red and yellow-light absorption and blue-light scattering that explains why the sky looks blue.

So perhaps I shouldn’t poo-poo the colorful, common blue jay. They are said to have complex social systems, mate for life, and use tools in captivity. Their mysteries are not all solved, either. The flock that crossed in front of me may actually be migrating. But only about 20% of blue jays migrate, and the ones that do may not migrate every year. Birdwatchers at Hawk Ridge in Duluth, MN, count blue jays along with migrating raptors. On September 16th, 2013, they counted 5,627 blue jays, bringing the season total of southbound birds to about 25,000. And yet, many stay behind as our feeder friends all winter long.

The movements of blue jays may even be responsible for the oak leaves dancing on the wind and rustling on the road. Ten thousand years ago, a barren Wisconsin had just emerged from under a mile of ice. From pollen samples in the soil, we know that nut-bearing trees like oaks moved back north much faster than trees with wind-blown seeds. Blue jays, who can carry 5 acorns at a time, airlifted the seeds north, cached them under the leaf litter, and essentially planted us a new forest.

With climate change once more altering our landscape, perhaps blue jays will again help move oaks and hickories north to fill in where other less heat and drought tolerant trees may die out. Cheerful feeder friend, or wily villain? Maybe neither one does justice to the beautiful, tree planting blue jay.

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



Friday, October 17, 2014

How Mushrooms Can Help Save the World


“Brace for impact,” advised a gray-bearded man wearing wire-rimmed glasses. Shaggy, dark brown curls tumbled out from beneath his tawny, felted hat, and the hundreds of mycologists in the audience could feel his excitement. “And can someone turn out the lights?” he continued as the slide on the screen revealed the phrase “Biodiversity is Biosecurity” against a luminous blue background.

Paul Stamets is a visionary, award-winning mycologist (person who studies mushrooms), author of “Mycelium Running – How Mushrooms Can Help Save the World,” and founder of Fungi Perfecti, a company that grows and sells mushroom products for “Home and Garden, Field and Forest, People and Planet.” He believes that mushrooms, and the network of root-like fungal mycelium that produces them, can heal the planet (including humans.)

Images of networks flashed on the screen as Paul reflected on the similarities between systems of brain neurons, galaxies, dark matter, the internet, and fungal hyphae. What do they all have in common? Redundancy in their information pathways. If one route is broken, several alternatives can carry the data. “I calculated that every footstep I take impacts more than 300 miles of mycelium,” he shared. All that mycelium in a small place means many opportunities for connection and re-connection. Humans would do well to imitate the resiliency of those networks, Paul suggests.

Fungi, Paul argues, are both the internet and the immune system of the Earth. Mycorrhizal fungi, who form partnerships with the roots of most plants, extend their root-like hyphae throughout the forest floor. As I described with black trumpet and hedgehog mushrooms a few weeks ago, the fungus grows a layer of hyphae around the tree’s tiny roots, and even in between the cells of the roots. Then, the fungi stretches it network of hyphae out into the soil, and aids the tree in acquiring water and nutrients, especially nitrogen. Mushrooms, as they decompose, also cycle quite a bit of phosphorus in a forest ecosystem.

The mycelia not only benefit their main tree partner by extending the food- and water-gathering power of the roots, they also break down dead stuff – and even break down rocks – to make nutrients available to the tree. Chemical compounds that the fungi exude can ward off harmful fungi and bacteria, and help the forest maintain a suite of microorganisms essential for health and growth.

When a plant is attacked by pests, it often begins producing chemical defenses that make it less palatable to the insect. Other plants connected through the fungal “internet” get the message and can preempt an insect attack. In controlled experiments, plants not connected by fungal hyphae don’t have the same ability to communicate danger to each other.

In exchange for these services, the tree “pays” the fungi in photosynthates – the sugars that only green plants can produce through photosynthesis. Amazingly, the fungal network can also facilitate the sharing of sugars between trees of completely different species. When scientists shaded a Douglas fir tree, the fungi brought it sugars from a nearby birch. This is just one way that mushrooms can support the health of a forest.

The mycorrhizal fungi that partner with plant roots occupy a pretty unique niche in the forest. They often grow with just one or two types of trees. Many are choice edible and medicinal mushrooms (like my hedgehogs and black trumpets), but they are almost impossible to cultivate because of their specificity.

Saprophytic mushrooms, on the other hand, decompose organic material, and are absolutely critical to renewal in the forest. They turn dead stuff into healthy soil with plenty of nutrients for new life. Some saprobes can even decompose things like petroleum and fecal bacteria. They can act as living filters for pollution. And many edible species can be grown fairly easily in your basement or backyard.

Most of the audience already knows this. As members of the North American Mycological Association (NAMA) attending the Annual Foray, they’ve been seeking choice edibles and comparing notes on cultivating mushrooms all weekend, in addition to collectively picking and identifying over 364 species from the surrounding area.

Paul’s talk was not new to them, since he is a regular at their gatherings. I, in contrast, had only heard vaguely of his ideas, and had let his book drift to bottom of my reading list. His excitement for the subject sparked mine. Happily, I get to think about mushrooms and mycologists for the next few years, since I’m helping to organize the 2017 NAMA Annual Foray in Cable, WI! By then, we’ll know even more about how mushrooms can help save the world. Hope to see you there!

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

Friday, October 10, 2014

Bat in the Daylight

It was the type of morning when gray clouds replace the entire sky, and the smoky gold of maple leaves seem to replace the sun. After a day of heavy rain, a damp calm had settled into the woods. Nothing moved except the occasional crumpled leaf finally letting go. As I admired the scene from a second floor window, bigger movements caught my eye.

The erratic fluttering of a small, brown creature was confusing at first. Then it flew straight toward my window, only swerving away at the very last instant. In that moment I saw its big ears, tiny head, furry body, and brown-skinned wings clearly – bat! All summer I’d barely seen a bat—not due to their rarity, but to our differing schedules. Now I’d seen bats in the dark, bats at dawn, and this bat in the day, all in the space of a week.

In some cases, animals being active at the “wrong” time of day can be a sign of trouble. One of the symptoms of white-nose syndrome is that bats venture outside during the winter to replenish their stores of food and water, used up by frequent grooming to battle the fungus. Those bats should be reported to the DNR. Some people also worry that bats outside during the day are a sign that they have rabies. That’s possible, but rare. Bats get knocked down pretty quickly by rabies, have trouble flying, and generally go somewhere dark and quiet to die. Plus, only 6% of sick bats even carry the disease.

This bat was flying quite acrobatically, without any sign of poor health. In a series of swoops, dips, darts and quick turns, it seemed to be outlining the route of a new thriller rollercoaster—one that I would NOT like to ride. Around and around the clearing it swooped, catching insects I couldn’t see.

Hunger must be its motivation, I concluded. With lows in the 40s for several nights in a row, and heavy rains off and on, many night-flying insects have been grounded. Plus, the energy needed just to keep this little mammal’s body temperature high enough would have offset any nocturnal calories it could catch. In a canyon in Italy, a type of bat called the soprano pipistrelle has switched to daytime hunting almost exclusively for these reasons. They’ve found an area under the forest canopy with more daytime insects, and without predators.

This little guy must have decided that the risk was worth it, as he (or she) needs to bulk up quickly for migration and hibernation. Bats may also switch to diurnal hunting in early spring, when they are hungry from the long winter, and it is too cold at night for them and the insects to fly.

While the muted sunlight allowed me to see the bat, I could not even begin to imagine how it was seeing the world. Bats are not blind, and can see about as well as humans, especially in low light. Bats use their eyes to navigate around large objects and across the landscape. Of course, their most accurate way of “seeing” the world is through their amazing powers of echolocation.

Insect-eating bats shout out short bursts of sound, timed to their wing beats to save energy. (Fruit bats and others don’t use echolocation to the same degree, but they don’t live here.) Short silences between the sounds allow the bats to hear the echo of information coming back. Their brains—more advanced than the most powerful supercomputer—use the sounds to create highly accurate pictures of flying insects. Although the sounds have to be as loud as a jet plane in order to echo sufficiently off small, soft insects, they are too high-pitched for us to hear. Bats use tiny muscles to plug their ears while they shout, so they don’t deafen themselves.

Those high frequencies give bats a very precise picture of their prey: the size, whether the insects are hard or soft-bodied, their speed and direction of travel, and much more. But the sounds don’t travel more than a few feet. That’s why bats may swoop near you at night, but always veer away at the last second. (They might also be nabbing that pesky mosquito buzzing your ear.) Bats can “see” objects as thin as human hairs, so they can certainly see you, too. Lower frequency sounds would allow for a greater range, but at the expense of accuracy. Plus, if bats shouted in a frequency we could hear, the night would be a whole lot noisier!

Bats don’t just shout; they have several types of vocalizations. In the evening, just before emerging to hunt, bats “chatter” inside their communal roosts. Some of the chatter is low enough that we can hear it, but much is still above our audible range. Male bats of some species sing to attract females or ward off other males. Bats “honk” at each other in mid-air to avoid collisions, and pups call to their mothers.

Echolocation calls come in a few forms, too. There is a “search phase call,” which is composed of slower sounds used to find prey. A “tracking phase” ensues during the chase. Finally, as the bat closes in on an insect, it speeds up the sounds into a “feeding buzz” that can relay almost continuous information about the prey’s location and direction.

I first discovered those sounds while putting together the Museum’s “Nature’s Superheroes” exhibit. USFS biologist Brian Heeringa sent me several recordings of bat echolocation calls, transformed so that they were partially inside the human range of hearing. Catchy rhythms worthy of a late night dance party spilled out of the computer. Our exhibit committee listened eagerly to the tracks several times over, eventually choosing the liveliest calls for the exhibit’s “bat song wall.” You can come in and hear them, too!

Within an hour, the diurnal bat had disappeared. I hope he found somewhere safe to sleep. In his place, a flock of yellow-rumped warblers invaded the yard. They darted about with the same swooping flights. Unlike the bat, though, they perched briefly in between snacks. What were they all eating?

Stepping outside, I soon had the answer. Little specks of fuzz were drifting around -- woolly alder aphids on the move. (Read about them on the NC blog.) A mosquito buzzed my neck. (Come back, little bat!) Even on a gloomy fall day, the air is filled with life.

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


Friday, October 3, 2014

Bats in the growing darkness

Darkness encroaches on either side of my days. The growing shadows reveal new wonders and old friends, as does the lengthening daylight of spring.

When dusk falls before bedtime, I can step outside to watch stars sparkle across a moonless sky and northern lights dance above a silver lake. The dark collects everyone from their outdoor adventures, and gathers them inside for the evening. It feels right to eat dinner at six o’clock instead of eight-thirty.

When my alarm beeps before sunrise, dawn accompanies my morning yoga. It is harder to get out of bed in the dark, but gray light soon eases the entry into wakefulness, and flaming pink skies reward even the not-so-early bird. On weekends, the sluggish sun finally allows me to sleep in.

One morning last week, while watching that gray light turn lavender and pink, I caught a glimpse of movement through gaps in the silhouetted trees. Dark shapes that I’m usually too sleepy to see fluttered back and forth across the chilly dawn. Bats!

I wasn’t able to identify the species of bats zipping through the yard, but no matter which of Wisconsin’s seven bat species they are, fall is a challenging and potentially dangerous time. With amazing powers of echolocation, they are certainly comfortable in the increasing darkness, but not the increasing cold.

Little brown bats, a type of cave bat, are widespread and common in the Northwoods. They spend their summers hunting insects near water, and roosting in warm spaces like wood piles, trees, and your attic. Bats enter a period of torpor each day, where their metabolic rate and body temperature drop. Roosting in a warm environment allows them to keep their body temperature at a high level even while saving precious energy.

Through the winter, little brown bats also need their environment to provide a stable temperature. Lower temperatures that stay above freezing are ideal conditions that allow bats to slow down their metabolism and conserve energy. Winter periods of torpor last longer, but bats will still wake up in order to groom themselves, and sometimes to get a drink.

This time of year, little brown bats, big brown bats, northern long-eared bats, and eastern pipistrelles are all heading for the caves and old mines that serve as their hibernacula. According to Brian Heeringa, biologist with the US Forest Service in Washburn, our bats have already begun to move (toward the UP of Michigan and SW Wisconsin), and the ones I saw may be migrating through from even farther away.

While the caves that provide bats with shelter are integral to their survival, those same caves may now house the biggest threat to their existence. White-nose syndrome (WNS), a devastating disease caused by a soil fungus, is causing unprecedented mortality in cave bats across the eastern United States.

The fungus affects bats’ skin. Wings are especially vulnerable. Noses become whitened, too. Being cleanly creatures, infected bats wake up more often to groom themselves, thereby depleting their energy stores and becoming dehydrated. Up to 95% of bats in infected caves die over the winter.

WNS was discovered in southwestern Wisconsin just last spring, and only infected 2% of the bats in one cave. There are no confirmed sites in Minnesota…yet. Its spread is inevitable, though, and it is causing the most precipitous decline of North American wildlife in recorded history. This winter, the WI DNR will continue to monitor all the known hibernacula in Wisconsin for WNS. In mid to late winter, biologists will be swabbing noses, taking soil samples, and simply looking for signs of the fungus. You can check the spread maps at whitenosesyndrome.org for up-to-date information.

What I find fascinating—and hopeful—is that in Europe, where the fungus originated, bats are not extinct. Their populations have adapted to being less dense, with larger individuals. Lower densities probably slow the fungus’s spread, while the larger bats’ greater energy stores seem to allow them to wake up more often and groom away the fungus. Perhaps our bats will adapt in the same ways.

Presently, only bats that hibernate in caves are infected by WNS. Wisconsin also has three species of tree bats that migrate south for the winter and have not been affected by WNS. Hoary bats, silver-haired bats, and eastern red bats fly hundreds of miles south to the balmy weather in Mexico, Florida, or even Illinois. These bats face a different hazard, however—wind turbines.

Being curious mammals, bats seem to be attracted to wind turbines. During migration, many bats may travel through wind farms.  Getting too close either results in death by impact or in death by barotrauma. Barotrauma takes place when bats enter the area of low pressure just behind the spinning blades. The pressure differential causes the bats’ lungs to fill with fluid. Power companies can help by turning off the blades during the bats’ most active periods, which usually coincide with low wind speeds anyway.

Bats are amazing creatures, with many fascinating adaptations. I would much rather write about those adaptations than about the potentially devastating threats bats face. But if the bats are to survive these challenges and be there amaze and fascinate us in the future, they need our help and support now. We can all help protect their summer habitat and food sources, so that bats can survive this growing darkness and time of change to fly again in spring.

Visit your state’s DNR website, batcon.org, or the Museum’s current exhibit “Nature’s Superheroes,” for information about how you can help!

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