It was a beautiful day for a hike in Fairyland. This State Natural Area is named for the “relatively undisturbed old growth hemlock hardwood forest” that forms its core. Stands of mature, second-growth hardwoods surround the hemlocks, and ephemeral ponds poke holes up to the sky through the hemlocks’ dense green canopy. This forest was once owned by Mary Griggs Burke, founder of the Cable Natural History Museum. Legend has it that Mrs. Burke found solace in the groves as a child, and then, as an adult, set up fairy tea parties in the woods for her young friends. The sense of magic remains.
Our chilly morning meant easy walking on frozen ground, and bright sunshine added cheer to the crisp air, as we pushed through a branchy balsam fir thicket into the open, park-like hemlock grove. We paused to breathe in the primeval atmosphere.
Patchworks of emerald, olive, and chartreuse moss draped over soft, sunken logs. Hummocks and swales in the forest floor told tales of large trees, long fallen. Their huge root masses, ripped from the ground by a strong wind, had once risen above the soil. Rain, snow, and rot had knocked down the masses, crumbled their massive trunks, and now they lay like sleeping giants under the duff.
The ground-level caverns and raised root-knees of hemlock and yellow birch trunks gave us shadowy visions of the nurse logs and stumps their seeds had sprouted on long ago. The young, growing trees had embraced their damp, fertile nurseries, only to have the old wood vanish into the soil and leave empty space behind.
We all admired the cavities in the bases of trees, and examined them for signs of habitation. A few red squirrel middens, littered with piles of shucked cone brackets, spilled onto the ground. But Vivianne Hanke, who teaches fairy house making workshops for the Museum, had other ideas. “There’s a Fairy House!” she exclaimed quietly, pulling out her camera to take a photo of a castle-like mossy stump. “Here’s another one,” she murmured into the space left beneath a yellow birch’s roots. Soon we were all joining in her search. Almost any tree, we discovered, could be quickly inhabited by our imaginations.
With her eyes on the ground, Vivianne soon found another fairy home. “I almost stepped on it,” she chuckled, handing me the papery gray pouch. It didn’t look like much. A few leaf veins were still visible, but most of the case was reinforced with fine, tan-colored silk. “Promethea moth?” I said to the little cocoon in my hand; half-hoping that it would identify itself. While we were looking into stumps for fairies, here was the winter home of a real live fairy right under our feet.
Callosamia promethea are large, beautiful silkmoths, with black, tan, pink, and redidish-brown wings. Their caterpillars attach a leaf to its twig with an extra-strong lash of silk, pull the leaf around, them, and then spin a second tough, hairy chamber inside. Within those two layers of nearly impenetrable silk, the caterpillar forms its pupa and waits out the winter.
But when I took the cocoon home to examine it, I soon noticed a long groove in the back of the pouch. This cocoon had been attached to a twig along its entire length, not just from a thin, reinforced stem. With a few more queries on Google Images (the best way I’ve found to identify insects!), I soon came to the tentative identification of Hyalophora cecropia, the Cecropia silk moth, instead.
Cecropias are North America's largest native moth, and share a similar rich, black and reddish-brown coloration with Promethea moths. Fairies indeed. In an ideal world, a beautiful moth would emerge from this cocoon in mid-summer, cling to someone’s screen door under the porch light, find a mate, lay eggs, and then expire peacefully in the night.
Unfortunately, this cocoon only contained the dried, crumbled remains of a parasitized pupa. I almost wish I hadn’t opened it. Like Schrödinger's cat, if I didn’t know, I could still imagine that a viable moth pupa rested inside.
Glancing down at the empty shell resting near my keyboard, my mind wandered away from the death I’d found, and returned to a series of online photographs of a plump, fluorescent green caterpillar with multi-colored spikes, spinning a similar home. A living creature had made this!
Almost anything, we discovered, can be quickly inhabited by our imaginations.
For over 45 years, the Cable Natural History Museum has served to connect you to the Northwoods. Come visit us in Cable, WI! We are currently constructing our new exhibit: “Lake Alive!” which will open May 1, 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.