Woolly Weather

A blustery fall wind swept away any warmth from the pale sun. Brown and yellow leaves skittered across the pavement. As I bent down to dip my hands in the lake, my arm (wrapped in fuzzy fleece) brushed the seed head of a burr marigold—so named because the cheery yellow flower matures into a cluster of pokey stick-tight seeds. Yet another sign of the season…

Distracted, I meandered back toward the car, picking little two-pronged seeds out of my armpit as I went. Then...whoa!  Something caught the corner of my eye, and I pulled my foot back from its next step. There, in the middle of the parking lot, was a woolly bear caterpillar. Not the most exciting find, but it would have been unpleasant for both of us if my shoe had continued on its original path.

I’ve always enjoyed seeing these fuzzy, black and brown-striped critters. As a kid I tortured them—poking one to watch it curl into a ball…patiently waiting until it uncurled...and the poking it again. You’ve probably had your own encounters with these cute little critters, no matter what age you happened to be. A few years ago, while I was teaching in Maine, my class found a woolly bear’s hairy cocoon in the woods. The students just shook their head at my enthusiasm for the discovery.

Seeing this woolly bear didn’t strike me as anything spectacular, but I took some photos anyway, because a friend had asked me about the caterpillar’s famed weather predicting skills. My research turned up a great story about that, and so much more.

Back in 1948, Dr. C. H. Curran, curator of insects at the American Museum of Natural History in New York City, wanted an excuse to get out of the city and enjoy the fall colors. He decided that the question of woolly bears’ weather prediction skills needed some field research (sounds like a great excuse to play hooky from work to me!), and took his wife a nearby state park. They gathered as many woolly bears as they could find, and measured the sizes of the black and brown stripes. This was so fun that they invited friends the next year, and began calling themselves The Original Society of the Friends of the Woolly Bear.

For eight years they “gathered data” in the beautiful fall woods. At first, it seemed like they were on to something. Several years in a row, the brown stripes took up more than a third of the caterpillar’s thirteen body segments, on average. Folklore says that wider brown stripes forecast milder winters, and that did indeed play out for Curran. Then came the year that two groups of caterpillars in neighboring habitats gave opposing forecasts. That year, Curran gave up.

As it turns out, some scientists now think that the width of the brown band IS related to the weather—of the previous spring. Each time the caterpillar gets too big for its skin and molts, one black segment changes to a brown segment. So, a w-bear who starts eating early (they are generalist feeders who eat a variety of plants), during a mild spring, will have a wider brown stripe by the following fall. A caterpillar who gets a late start, perhaps due to snow in April (not that we know anything about that!), will likely have fewer brown segments before the growing season ends again.

So, with one riddle solved, we’re ready for another one. Why do you see so many woolly bears crossing the road this time of year?  To get to an overwintering site, of course! Like many northern critters (bears, for example), woolly bears are short-distance migrants who need to travel a little ways to find a nice place to spend the winter. And they can get there fast (for a caterpillar) traveling at 0.05 miles an hour, or about a mile a day.

Beneath a rock, under a log, in a bark crevice—almost any protected place will do for an overwintering woolly bear. Warmth is not a major factor, since these little guys will freeze solid, and thaw, and freeze again, many times throughout the winter. On a warm day, they may even get out and crawl around.

If a tomato spent the winter like a woolly bear, it would soon be mush. But woolly bears use chemicals known as cryoprotectants to safeguard living tissue against damage from freezing and thawing. Woolly bears who live in the arctic (the species we know as well as some relatives) may take 14 years to complete their life cycles. They freeze solid every winter, and grow just a little bit during each brief summer.

Our Wisconsin (or Minnesota) woolly bear only needs two years to complete its life. In spring, it will thaw and resume eating. Once large enough, the caterpillar spins itself a cocoon using silk and its own hairs. In two weeks, it metamorphoses into a pale yellow Isabella tiger moth. In another two weeks, the moth will mate, lay eggs, and die.

Tiger moths, in the family Arctiidae, are amazing, colorful creatures in their own right. Some tiger moth caterpillars eat toxic plants, just like monarch caterpillars, in order to protect themselves against predators. The toxin persists in the adult moths, who use bright warning coloration to tell potential predators that they taste bad. Since one of their main predators—bats—can’t see colors in the dark, the moths emit ultrasonic sounds to warn bats of their unpalatability.

All the moths are surely dead by now, and their offspring, the caterpillars, are racing toward their overwintering rocks. I hope the one I almost stepped on found a cozy place in the leaf litter. With snow in the forecast, I’m glad I overwinter in a house. I wonder how mild or harsh this winter will be?  I wish a woolly bear could tell me!

The Forest Rainbow

Sunlight streamed through a golden canopy of maple and poplar leaves, bathing the hiking trail in warm energy. The group chatted merrily, their lively conversations keeping pace with eager hiking boots, bright moods reflected in bright clothes. Pink and purple leaves on the maple-leaf viburnum added color to the understory, while the last remaining berries on blue-bead lily and blue cohosh stalks provided accents. Overall, the fall forest was a rainbow of color.

But not all the most interesting colors were immediately obvious. As my boot scuffed the dry brown leaves on the side of the trail, a glimpse of vivid color caught my eye. Buried beneath the fading leaf litter was a bright red fungus. As I brushed the crinkly leaves aside, my fingertips relished the smooth, slippery texture of the mushroom’s surface.

Aptly named the scarlet waxy cap, clusters of this beautiful mushroom has been livening up most of my hikes lately. Earlier in the fall, their particular shade of red, with yellow on the margin of the cap, blended in perfectly with fallen maple leaves. Now, although buried under more leaves, the colors stood out distinctly.

Since this mushroom is easy to identify, it is tempting to harvest it for my kitchen. Indeed, it is reported as “mild tasting” and is eaten throughout its habitat in Europe and Asia. However, since some mycophagists (people who eat mushrooms) in North America have reported adverse reactions to the scarlet waxy cap, I have decided to enjoy it solely in the woods.

After examining that first patch of waxy caps, I began to see them peeking up among leaves all along the trail. Then I started seeing fungi everywhere! Lichens (composed of fungus and algae) encrusted all the trees, shelf fungi gave trunks interesting silhouettes, and rows of white turkey tail mushrooms lined every fallen log.

Turkey tails are some of most common mushrooms found on wood in the world. They are a type of bracket fungi, meaning that they form thin, leather-like and leaf-like structures in concentric circles. When you flip a scarlet waxy cap upside down, you find rows of bright yellow gills. But, on the underside of a turkey tail, you find tiny pores.

It is the upper surface of a turkey tail mushroom that provides its name, though. Concentric rings of brown, orange, maroon, blue, and green remind us of the iridescent tail feathers on a wild turkey. While not as bright as the waxy cap, the turkey tail has subtle beauty, and is worth close examination. It also has medical uses.

Turkey tail mushrooms have been used to treat various maladies for hundreds of years in Asia, Europe, and by indigenous peoples in North America. Traditionally, our ancestors boiled mushrooms in water to make a soothing tea. Records of turkey tail brewed as medicinal tea date from the early 15th century, during the Ming Dynasty in China. A few years ago, my Aunt Nan used turkey tail tea to boost her immune system during a battle with cancer, and she outlived the doctor’s predictions by several years. Last summer, a promising clinical study showed that the turkey tail mushroom (Trametes versicolor) improves the immune systems of breast cancer patients.

As I examined a log covered with little bracket fungus, I noticed that some of them looked purple around the margin instead of the typical white. When I broke one off to examine it more closely, I found a very different mushroom!

The plain white and cream cap of a violet-toothed polypore hides a gorgeous lavender underside. If you tilt it, the color becomes almost iridescent as light bounces around the brightly colored pores. While not medicinal, this mushroom always makes me smile. I can’t wait to bring my four-year-old niece Kylee mushroom hunting, so she can look for her favorite color on every fallen log.

What she won’t see as easily is the true body of the fungus. Scarlet waxy caps, turkey tails, and violet toothed polypores are saprophytic fungus, meaning that they decompose wood to obtain nutrients. The mushroom you see is simply the reproductive structure, tasked with releasing spores. The true work is done by a network of fungal cells (called mycelium) penetrating the decaying wood. One analogy is that the mushroom is like an apple, with the mycelium is like the tree.

You can sometimes find a web of black or white mycelium under the bark of a tree, beneath a rooting log, or under thick leaf litter. By some accounts, the world’s largest known organism is an interconnected web of genetically identical mycelium in Oregon’s Blue Mountains. This honey mushroom occupies 2,384 acres of soil (approximately 1,665 football fields) and could be as ancient as 8,650 years old.

All those mycelium are extremely important links in the food chain, since they play an enormous role in recycling nutrients from old plants and animals into new plants and animals. Can you imagine a forest without fungi? In the absence of wildfire (another decomposer) dead trees and plant debris would pile up horribly, and new trees would not have enough nutrients to grow.

As our hike ended, the chatter continued right on in to the cars. What fun it was to take a closer look at all the components in the forest’s rainbow on a beautiful fall day!

Migration Season at Hawk Ridge

“Hold it like an ice cream cone,” instructed Gail Johnejack, Education Director at Hawk Ridge Bird Observatory, as she skillfully wrapped her hand around mine, and guided my fingers into a careful grip on feathers and legs. When she transferred the bird into my care, I could feel the heartbeat in my own skin. A breeze ruffled the Sharp-shinned Hawk’s feathers, and I imagine we were both eager for it to continue its long migration journey. Beyond the bird stretched the city of Duluth, and the shimmering water of Lake Superior.

Hawk Ridge in Duluth, MN, is one of the top five hawk migration sites in North America for overall numbers and diversity of species. Each fall, about 82,000 raptors pass through this bottleneck on their southern migration. Understandably reluctant to cross a large body of water, the birds funnel southwest along the shore of Lake Superior. The high, rocky outcrop of Hawk Ridge Nature Reserve makes a great viewing platform, and people come together from all over the country to watch the migration here.

Harry, a Hawk Ridge volunteer, lives in central Minnesota, and drives three hours to volunteer a few days each week between September 1 and October 31. Harry is retired, like many volunteers, and enjoys interacting with the other main type of volunteer—college students fulfilling requirements for courses.  Harry loves his job, because “volunteers and visitors both find commonality and community in the birds – they draw us all together as a group. It keeps me young!” says Harry.

The natural setting is also a bonus. Bright sunshine, a warm breeze, and a terrific view are a stunning combination. Even chilly gray days have their own beauty. Harry likes the full spectrum. “When we hawk watchers arrive on the first of September we look down on the city in full summer green. By the time we leave on October 31, most of the leaves are gone. We are blessed with seeing the complete transition of fall.”

I gripped the Sharp-shinned Hawk carefully, amazed at both its sturdiness in my hand, and also the strength I could sense in its muscles. Erik Bruhnke, Count Interpreter, positioned himself just over the cliff, camera in hand. All day, Erik alternates between spotting and identifying birds, answering visitors’ questions, and taking photos of hawk releases. He is a wealth of information, and one of the reasons Harry loves his volunteer gig.

“I watched birds all my life, but I’m not a bird watcher,” Harry says humbly. “I’m just trying to become one! One of the benefits of Hawk Ridge is that amateurs can really learn from all the real birders that are here.” Erik is equally thrilled the arrangement. “Teaching is the best way to learn. Working here really helps me learn about birds on a deeper level.”

I learned a lot from Erik, too. For instance, the bird in my hand, a Sharp-shinned Hawk, is an agile and acrobatic flier, able to navigate dense woods at high speeds by using its long tail as a rudder. Short, rounded wings help Sharpies zip through tight spaces after small birds. During migration, they leave the dense forests of their northern nesting grounds and take to the open sky.

“Now you’re going to be the Statue of Liberty,” Gail instructed. “Hold your arm up high. When Erik counts to three, give it a little toss into the air.”

I raised my right arm high—thrilled to hold such an amazing creature for even a few seconds—and thrilled to be a part of its freedom. “One...two...three!” counted Erik. I released my grip with a gentle toss, and watched in awe as the hawk took flight. It swooped down below the cliff, and darted around trees before disappearing from sight. Close on its tail, three more hawks materialized out of the north, and zipped past the eager crowd.

Today, with a south wind, I wasn’t expecting to see much. Why would raptors fly with such a headwind? But, to my great delight, Sharp-shinned Hawks, American Kestrels, Merlins, Peregrine Falcons, Ospreys, and even Northern Goshawks zoomed past low enough to identify with the naked eye. Rain a few days ago delayed migration and created a backlog of birds. Now, the southerly winds force the birds to fly low, within easy view, and where they can be baited into the nets that researchers have set up.

Researchers carefully extricate each bird from the net, take a variety of measurements, and attach a numbered band to its leg. About three percent of birds banded here are recaptured. “Our utmost priority is to keep the raptors safe,” assured Gail. “When a raptor is captured for banding, it is held for a very short time, and then we let it get on its way.”

The bird I just released has a band, and if researchers recapture it again, Hawk Ridge will be notified. Since I sponsored the bird’s release, (with a donation to the private non-profit Hawk Ridge Bird Observatory) they will also let me know that this bird I connected with is alive and traveling.

“It’s hawk migration season!” exclaimed Gail. “We love having people come and visit and learn about this great migration event!” If you would like more information on the migration at Hawk Ridge, visit their website: www.hawkridge.org or find them on Facebook, or on their blogspot—http://hawkridgeblog.blogspot.com/.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI, at 13470 County Highway M. The current exhibit, “Deer Camp: A Natural and Cultural History of White-tailed Deer,” opened in May 2013 and will remain open until April 2014.

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/.

Sharpies at Hawk Ridge (combined)

“Hold it like an ice cream cone,” instructed Gail Johnejack, Education Director at Hawk Ridge Bird Observatory, as she skillfully wrapped her hand around mine, and guided my fingers into a careful grip on feathers and legs. When she transferred the bird into my care, I could feel the heartbeat in my own skin. A breeze ruffled the sharp-shinned hawk’s feathers, and I imagine we were both eager for it to continue its long migration journey. Beyond the bird stretched the city of Duluth, and the shimmering water of Lake Superior.

Hawk Ridge in Duluth, MN, is one of the top five hawk migration sites in North America for overall numbers and diversity of species. Each fall, about 82,000 raptors pass through this bottleneck on their southern migration. Understandably reluctant to cross a large body of water, the birds funnel southwest along the shore of Lake Superior. The high, rocky outcrop of Hawk Ridge Nature Reserve makes a great viewing platform, and people come together from all over the country to watch the migration here.

It’s not easy, though, the migrants of are often tiny specks against the blue. Raptor biologists here have a special trick for getting close-up views of the hawks – bait. Using a technique a lot like fishing, researchers pull the string on a lure to make it look like an injured bird. When a raptor swoops down for an easy meal, it becomes tangled in one of a series of nets. Researchers carefully extricate it from the net, take a variety of measurements, and attach a numbered band to its leg. “Our utmost priority is to keep the raptors safe,” assured Gail. “When a raptor is captured for banding, it is held for a very short time, and then we let it get on its way.”

About three percent of birds banded here are recaptured. Based on the data collected from recapturing banded birds, sharp-shinned hawks migrating over Hawk Ridge generally head southeast to Illinois, and then southwest toward east Texas and Mexico, following the prevailing wind pattern.

Sometimes naturalists bring a recent captive down from the remote banding station so that folks on the overlook can get a better view. Moments after we arrived, two naturalists called everyone over to see a couple “sharpies” in hand. To prevent the hawks from hurting the humans or themselves, the naturalists held their wings, tail, and legs gently but firmly in the fist of one hand. The birds, both hatch-year females, looked quite calm.

Sharp-shinned hawks are the smallest hawks in North America, and have the biggest size difference between males and females. Females are up to one-third bigger than males, and this size difference means that they focus on different sizes of prey. Males tend to hunt smaller birds, such as sparrows, while females can concentrate on larger prey, like robins. This has two big advantages: males and females do not compete for the same food source, and chicks can get appropriately sized food as they grow.

During the first few weeks after hatching, the female sharp-shin broods the chicks while the male hunts and brings in small songbirds. He typically removes and eats the head before delivering the meal. As the chicks mature, the female joins in the hunting and brings larger prey for the hungry fledglings.

Sharp-shinned hawks are agile and acrobatic fliers, navigating dense woods at high speeds by using their long tail as a rudder. Short, rounded wings help them zip through tight spaces after small birds. During migration, they leave the dense forests of their northern nesting grounds and take to the open sky.

To help make the journey easier, these and other hawks will ride thermals, which are rising pockets of warmer air, formed by the uneven heating of the surface of the Earth. Thunderheads are visible thermals, where clouds of water droplets show just how high the warm air is climbing. When you see turkey vultures or other birds soaring in lazy circles without flapping, they are riding thermals.

For every mile a bird rises on this avian elevator, it can coast downwind seven miles without flapping. Still, sharp-shinned hawk’ migration from the top of this continent to the bottom takes strength, endurance, and stored energy. In order to be ready for the journey, these small hawks grow furiously—going from egg to adult size in just over 7 weeks.

I gripped the sharp-shinned hawk carefully, amazed at both its sturdiness in my hand, and also the strength I could sense in its muscles. Erik Bruhnke, Count Interpreter, positioned himself just over the cliff, camera in hand. All day, Erik alternates between spotting and identifying birds, answering visitors’ questions, and taking photos of hawk releases. He is a wealth of information.

“I watched birds all my life, but I’m not a bird watcher,” Harry a Hawk Ridge volunteer, says humbly. “I’m just trying to become one! One of the benefits of Hawk Ridge is that amateurs can really learn from all the real birders that are here.” Erik is equally thrilled the arrangement. “Teaching is the best way to learn. Working here really helps me learn about birds on a deeper level.”

Harry is retired, like many Hawk Ridge volunteers. He enjoys interacting with the other main type of volunteer—college students fulfilling requirements for courses.  Harry loves his job, because “volunteers and visitors both find commonality and community in the birds – they draw us all together as a group. It keeps me young!” says Harry.

The natural setting is also a bonus. Bright sunshine, a warm breeze, and a terrific view are a stunning combination. Even chilly gray days have their own beauty. Harry likes the full spectrum. “When we hawk watchers arrive on the first of September we look down on the city in full summer green. By the time we leave on October 31, most of the leaves are gone. We are blessed with seeing the complete transition of fall.”

And I’m thrilled to help this hawk transition back to its journey. “Now you’re going to be the Statue of Liberty,” Gail instructed. “Hold your arm up high. When Erik counts to three, give it a little toss into the air.”

I raised my right arm high—thrilled to hold such an amazing creature for even a few seconds—and thrilled to be a part of its freedom. “One...two...three!” counted Erik. I released my grip with a gentle toss, and watched in awe as the raptor took flight. It swooped down below the cliff, and darted around trees before disappearing from sight. Close on its tail, three more hawks materialized out of the north, and zipped past the eager crowd.

“It’s hawk migration season!” exclaimed Gail. “We love helping people experience this great event!” 

Elk and Wildness

The spicy smell of sweet-fern hung in the mist as we stepped quietly onto the forest road and gingerly shut our car doors. Laine Stowell, DNR Elk Biologist, slung his telemetry equipment, a bull elk bugle call, and a cow elk call over his shoulders. The remains of a damp night lingered. Low clouds merged with ground fog, and water droplets clung to every leaf blade.

The wildness of the 1,530,647 acre Chequamegon-Nicolet National Forest seemed heightened by the fog. For me, its wildness is also enhanced by the return of another species. Elk were extirpated from Wisconsin in the 1800s due to over hunting and a rapid decline in habitat. In 1995, twenty-five elk were released into the National Forest near Clam Lake, and the DNR now estimates the population to be about 170 animals.

Through the mist we walked, each lost in our own quiet thoughts. Where the road intersected with a power line, Laine paused, and we gathered in a loose group. Using the cow call, he made low bleating sounds. Then, switching to the bull elk call, he let out a series of haunting bugles.

If another bull was listening, we hoped that he would think we were a herd of cows being protected by a bull. "They basically gauge each other by the masculinity of their bugle…” If Laine sounded weak, maybe another bull would challenge him. Then we would get to hear a real elk bugle, and possibly even see one come in to investigate.

“[Bugling] also plays a function in that it synchronizes the cows estrocycle and makes the breeding of the cows more efficient," said Stowell.

Breeding and calving was pretty successful last year. According to Laine, 35 to 37 new calves were expected. Of those, 23 were actually found by DNR staff and volunteers and fitted with tracking collars that will provide future information about their survival.

In past years, more males than females have been born. This year, for the first time in this herd, the ratio included three more females than males. The reason for this is still a point of speculation, but researches have noticed that cows with a high proportion of kidney fat tend to have more male calves. The abundance of males in the past could suggest that this is excellent habitat, and elk are thriving in their new home, resulting in good nutrition and fat storage.

But why the change? Laine suspects that wolves might be chasing the cows more often, and keeping them leaner. Wolves do account for an increasing proportion of elk mortality. When elk were reintroduced, wolves had to re-learn how to effectively kill this new prey, since elk are about five times the size of a white-tail deer. Two local wolf packs have learned the game well, and account for most of the wolf predation.

Researchers aren’t too troubled by this--it is a natural and expected part of both elk and wolf ecology--but they would like to see the herd grow more quickly. Laine takes it all in stride, and just accepts the challenge of restoring a prey population when its predator population has already successfully restored itself.

One thing that land managers and wildlife ecologists hope to accomplish together is improving elk habitat. Mature forests provide fewer tasty, tender new twigs and less of an escape advantage to elk. On the other hand, aspen clear-cuts provide plentiful forage for the elk. Some describe them as “dog-hair stands,” because the trees grow as thick as the hair on a dog’s back. Laine surmises that wolves have a much harder time running through these thick young trees than the lanky elk.

Based on telemetry data, no elk have been preyed upon by wolves while using the one large clear-cut in their range. This supports the value of such land management to the elk recovery. Smaller, patchy, clear-cuts do not provide the same benefit. While they may have tasty forage, wolves soon figure out that the elk gather there to eat. Then the wolves can easily chase the elk into the mature forest surrounding the aspen regeneration, and it becomes the wolves’ diner instead.

The group walked a little farther into the forest, passing an open meadow where Laine often sees elk. At the top of a small knoll, we pause again, and Laine gives his calls. As we listen quietly for a response, chickadees flit and chatter in a nearby pine. In the distance, a mystery bird squawks, and blue jays squawk back. Laine bugles again. This time, a loon responds with its lonely wail. Then a hiker’s stomach responds with a hungry growl. It’s almost time to head home.

Finally, from the misty distance, a real bull elk bugles in response. A minute later, another elk bulges from farther away. We listen for another minute or two, then walk back to the cars under a brightening sky. I pluck a ripe blackberry from an overhanging bush and savor the flavor of wildness in the morning.

For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI, at 13470 County Highway M. The current exhibit, “Deer Camp: A Natural and Cultural History of White-tailed Deer,” opened in May 2013 and will remain open until April 2014.

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/.