A loud scratching inside the wall pulled me awake. The frantic scrambling was punctuated by minutes of silence, then more scratching. The clock glowed at 2:34 AM.
In my sleep-deprived stupor, I silently cursed Melissa Hogfeldt, Museum Intern, for bringing a rat into the staff house and keeping it in her closet without telling us. I tossed and turned, waiting for each new bout of scratching to begin, startling awake each time it did.
Finally, I moved out onto the couch and fell asleep in the gray morning light. When I stumbled downstairs for breakfast, Melissa was just heading out the door to bike to work. “Did you get a pet rodent?” I asked, clearly peeved, but trying to give her the benefit of the doubt. “No” she replied, obviously innocent, and confused. So I explained to her my sleepless night.
After lunch, when I called my dad to remind him to edit my Natural Connections article, I complained about my awful night. “I bet it is a flying squirrel,” he said, “at night, in the summer, up north...it must be a flying squirrel.”
Flying squirrels are amazing little rodents. They don’t actually fly, but glide on a flap of skin, called a patagium. It stretches between their front and hind legs, and is held out wider by an extra bit of cartilage on their wrist called a styliform. These three-ounce acrobats can turn 90 degrees around an obstacle in the air. A flip of their thin, flat tail changes their trajectory upwards for a smooth landing.
Immediately after landing, the squirrel will run to the other side of the tree trunk, just in case a predator spotted it in the air. Fascinating as these critters are, I almost wished I was a flying squirrel predator (a club that includes weasels, coyotes, foxes, and many more) after my short night!
After a failed attempt at an afternoon nap, I started making dinner. Mmmm…chanterelles…freshly gathered from the woods. Mycophagy (eating mushrooms) is one thing I have in common with flying squirrels.
In the Pacific Northwest, flying squirrels eat fungi and lichens almost exclusively. Many of the species they prefer are truffles, which fruit underground and release a strong scent when ripe. Therefore, surprisingly, the flying squirrels spend a considerable amount of time rooting around on the ground. Then, just as a black bear spreads berry seeds, the squirrels excrete fungal spores.
Many of the fungi the squirrels eat are mycorrhizal species that live on tree roots and assist the tree in acquiring nutrients and water, while receiving sugars from the tree’s photosynthesis (myco=fungi and rhizal=root).
The squirrels are so good at spreading spores, and the fungi are so important to the trees, that flying squirrels are considered “keystone species” in the Pacific Northwest. This simply means that they have disproportionately large effect on their environment relative to their abundance.
Although flying squirrels and their ecological relationship have not been well-studied in Wisconsin, we can assume that they fill a special niche in the Northwoods, too. We do know that Wisconsin flying squirrels have a more varied diet, which includes nuts, seeds, fruits, berries, insects and bird eggs.
As I finished frying up my mushrooms, Museum Intern Kellie Solberg joined me in the kitchen “Did you find your rodent yet?” she asked, “because I think I did…in the toilet.”
His little pinkish-gray nose with long whiskers just broke the water surface, while pink ears floated erect in the porcelain bowl. His long, flat tail extended down the tube. On the seat were muddy footprints. Below the ceiling vent, the floor was scattered with rodent-chewed frass. RIP, little guy.
Normally, Northern flying squirrels like to nest in cavities in live trees in older forests. The live branches and leaves must provide better cover than the bare branches of snags, and a home site they like will stay standing longer if they choose live over dead wood. If good tree cavities aren’t available, squirrels may even nest in the tangled mass of a “witches broom” growth in a spruce tree, or they will build a leafy nest, or “drey,” similar to gray squirrels.
I suppose an opening on our roof looked like a good cavity, and this squirrel decided to include our house in its den rotation. Now, it resides in our salvage freezer, awaiting taxidermy.
As mad as I was about my sleepless night, I’m sorry about the way it all ended. Northern flying squirrels are a “species of special concern” and a protected wild animal in Wisconsin. They may be locally abundant, but are not widespread. If you see one in the woods, count yourself lucky! If you see one in your toilet, well, I’ll let you decide.
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/.