Blane Klemek: Minnesota’s resident wildlife tough it out through the winter
(Klemek is the DNR Area Wildlife Supervisor in Detroit Lakes. You can contact him at firstname.lastname@example.org.)
The thermometer read minus 22 degrees a few mornings ago at my house in the woods. The snow squeaked underfoot on my way to the shed to get the morning’s supply of black-oil sunflower seeds for filling the birdfeeders — squeak, squeak, crunch, crunch as I walked to each of the feeders holding a plastic pitcher full of seed.
Although rays of light were just beginning to penetrate the dark cold, not a bird or squirrel was stirring. It would be awhile, I thought, before any signs of life would emerge from tree cavities, the boughs of conifers, underneath blankets of snow, and even from wood duck houses and other bird houses scattered throughout the property. Yes, even artificial nest boxes will house some of Minnesota’s wintering wildlife.
Just to make sure I was right, I stopped beside a chickadee roost box that I have erected near the feeders. The box resembles a smallish wood duck house, but has near its bottom a small hole for birds the size of chickadees — a species well known for its penchant of roosting together in tree cavities. Sure enough, upon removing the top lid, a half a dozen chickadees were roosting inside the structure.
But chickadees aren’t the only of Minnesota’s resident wildlife toughing it out through all four seasons; they and others have evolved to handle most anything Mother Nature can dish out. For example, the adaptable ruffed grouse actually fares best when snow is deep enough and is the right consistency for burrowing into. Ruffed grouse are well noted for their headfirst dives into soft snow to escape cold winter days and nights. In fact, the snow on the ground right now is perfect as far as the ruffed grouse is concerned.
A snow-roost, as it’s often called, is nothing more than a small burrow that a grouse creates after the bird has either crash-landed into the snow or forces its body into soft snow by essentially burrowing into it. For any grouse to accomplish this, the condition of the snow has to be just right. At least seven or more inches of fluffy snow is required for a ruffie to snow-roost.
Ruffed grouse are as “snug as bugs in a rug” inside their snow caves. Not only is the bird less visible to predators, snow roosting protects them from bitter cold temperatures, wind, blizzards, and the like. Snow is ideal insulation that helps grouse conserve valuable energy throughout the long winter months. A snow roost can actually be 50 degrees warmer than the ambient outside air temperature!
When it’s time to feed, or if they sense the approach of an enemy, they stick their head out of the snow and take a peak. If the coast is clear, or danger is eminent, the grouse immediately vacates his roost. Ruffed grouse have also evolved special feet that help them walk on top of the snow. Little comb-like projections that grow laterally along the sides of their toes act as snowshoes for better support on the snow and to grip ice-covered branches while they forage on trees’ buds.
Some species of mammals turn a different color during the winter months. Snowshoe hares and weasels turn snow white, except for the tips of the hares’ ears and the tips of the weasels’ tails. The pelage of both hare and weasel changes to brown by summertime, and are as cryptic in the summer with their brown coats as they are in the winter landscape with their white coats.
The snowshoe hare also grows dense fur on the pads of their front feet and oversized back feet. Not only does the additional fur provide great insulation against the cold, the extra fur also enhances a hare’s mobility in snow, just like snowshoes. They don’t call them snowshoe hares for nothing!
Regarding weasels, the tiny carnivore is the only one of its kind to turn snow white. Why only the weasel is anyone’s guess; no other member of its family — mink, otter, fisher and others — turns white. It could be that this evolved because of the weasels’ relatively small size.
Such tiny dimensions makes this animal vulnerable to predators like owls, foxes, coyotes, wolves and even members of its own family such as mink, fisher and pine marten. And since this animal makes a living as a predator itself, being able to blend into its environment — along with its tubular body design and quickness — equips the weasel with the means necessary to seek out and capture its prey of small and medium sized rodents, moles, and shrews under the snow or inside cavities in trees and logs.
As anyone who’s ever followed the tracks of a weasel knows, nothing goes unnoticed by weasels. Their tiny tracks and telltale, bounding gait across the snow will lead you to dozens of interesting discoveries. Snow, you soon learn, is no impediment to the weasel. In fact, like the grouse, snow is used to the animal’s benefit. The weasel knows that shrews, moles, pocket gophers, deer mice, and voles stay active throughout the winter in underground systems of tunnels underneath the snow. All the weasel does is burrow to where its prey lives and begins hunting.
Through many different adaptations and mechanisms, animals have found a way to survive the hardships of cold and snow. Whether it’s chickadees huddling together in a tree cavity, a grouse spending the entire day or night inside a snow cavity, a hare hiding underneath a balsam bough completely hidden by it and the surrounding snow, or an invisible weasel slinking along the top of a snowdrift and suddenly disappearing below it, winter’s challenges are met headlong by Minnesota’s wildlife as we get out and enjoy the great outdoors.