Life Under Snow
Art: Jan Perkins
A gray, mid-winter’s day. Clouds hang low on the surrounding mountains, giving a stratified feel and limiting vision to a flat cross section of the closed-in horizon. Walking one of my favorite winter fence lines, I pause at a thick wooden gatepost marking the Swaner Nature Preserve boundary. Atop the post are the remains of at least three different mice or voles — leftovers from some raptor’s meal.
Continuing down the line, I find similar remains at each post: morsels of blood-red innards against white snow at the base of one, yellowed buckteeth and the tip of a whiskered nose perched on the next, here the hind feet, legs and tail, there chunks of fur scattered about the windswept surface. I pick up a piece of fur expecting animal weight, but it is feather-light. No flesh at all, just the fur, neatly peeled and discarded.
A red-tailed hawk skims low across the snowscape, only inches above the surface to limit the distance from its own shadow and hence any warning to prey. In one spot, mud and grass are scattered on the snow where a fox or coyote has dug for a meal. In another, a slight depression in the snow and the delicate imprint of outstretched wings reveal the hunting touchdown of a hawk or an owl.
I wonder about the unseen community of voles, mice, gophers and ground squirrels who live beneath Park City’s famous snowpack. In addition to Montane voles, long-tailed voles, sagebrush voles and wandering shrews, all known commonly as field mice, the subterranean society here includes deer mice, house mice, northern pocket gophers, least chipmunks and Uinta ground squirrels. With the exception of the chipmunks and ground squirrels, who hibernate through the winter in underground burrows and cavities, our rodent population is active throughout the winter.
Turns out they’re active in the, ahem, boudoir as well. Other than the gophers, who breed just once a year, our local rodents have explosive reproduction rates with large multiple litters throughout the year. An acre of open land can house anywhere from a handful to several hundred, even a thousand or more, mice and voles. That’s fortunate for the resident raptors, foxes, coyotes and weasels, because without these rodents, there’d be precious little for them to feed on through our long snowy winters.
Voles, mice and gophers eat roots, seeds and insects. Each species prefers slightly different habitat, but all build intricate systems of surface runways, tunnels and burrows that are used by a remarkable variety of other animals. In the springtime, just after snowmelt, if you’ve ever seen long cores of dirt running along the matted surface of fields or even your lawn, you’re witnessing the remnants of gopher tunnels through the snow. During winter, gophers pack dirt into their snow tunnels and then the spring snowmelt deposits the long “gopher cores” on the ground.
If it weren’t for a healthy balance between rodents and their predators, we could easily be overrun by mice and voles. In fact, during a population explosion in Nevada in the early 1900s, vole populations ran as high as 25,000 per acre. Coyotes and foxes listen for rodents moving beneath the snow, then jump high in the air and pounce to collapse the surrounding snowpack before digging up their snow-trapped prey. Weasels and ermine have evolved with long, narrow bodies specifically suited to crawling through burrows and tunnels to prey on mice and voles. Falcons, hawks and owls use their highly attuned vision to spot the dark-furred rodents against white snow. Many of these predators are more successful hunting during winter than in warmer months.
I wonder about the remains along the outside boundary of the preserve. They are left there, of course, because the fenceposts make the best perches for hawks and falcons to eat their prey. But I like to think of the placement as a symbolic gesture, too, a statement, as if to say, this is the edge; from this point inward is a place reclaimed as wild.
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