Last week, I appeared in a couple of early morning segments on The Weather Channel’s America’s Morning Headquarters program. Broadcast live as I was interviewed by the show’s hosts via Skype from my own home, I wasn’t on the air very long. Yet what the show’s hosts wanted to cover was a topic that interests all of us: how do wildlife survive winter?
Indeed, how do they? One of the program’s hosts asked me, “What are some of the strategies that wildlife use to survive the winter?”
“Well”, I answered with a smile, “some leave!”
Yes, migration is a strategy employed by wildlife to “survive” Minnesota winters. Waterfowl, shorebirds, and songbirds galore, and many other species of birds, too, migrate south to warmer climes each and every fall.
Yet many other species of wildlife stay behind, be they birds, mammals, reptiles and amphibians, and insects and more. And all of these year- ‘round residents that stick out the cold, snow, and ice like most of us Minnesotans do, have various strategies to help them adapt to winter’s harsh conditions.
Though snow is beautiful and appears to some people as inhospitable, for many species of wildlife, snow serves as the ultimate in protection and opportunity.
Most avian predators, except for owls, have migrated southward. And even owls, though perfectly adept at detecting scurrying mammals underneath the snow by sound alone, are most successful at capturing those critters bold enough to venture to the surface of snow-laden woodlands and fields. Voles, though vulnerable to predation, nevertheless are better able to survive winter with adequate snow depth.
But not all predators are discouraged by snow depths. Weasels, which turn white in the winter (another survival mechanism), are more than capable of ferreting out small rodents from their systems of runways and nests under the snow.
Fox and coyote, too, with their keen senses of smell and hearing, are often observed hunting for mice and voles in the snow. When a fox detects the presence of prey, it will quickly spring into the air, pounce, and capture prey under the snow.
The insulative value of snow has not escaped the notice of wild creatures and humankind alike. In the avian world, ruffed grouse and sharp-tailed grouse are two year-around resident species of birds that frequently rely on snow as shelter.
Snow roosts, as they are called, are nothing more than spending the day or night underneath snow to escape the cold outside temperatures. Temperature differences can be dozens of degrees warmer under the snow. Grouse generally fly head first into snow and burrow into it for the warmth and protection that snow provides. These birds spend the coldest nights and stormy days inside their snow-burrows and will leave only for feeding.
Before emerging, grouse will stick only their heads out of the snow, look for danger, and explode from the snow in a feathered flurry of beating wings. The next time you’re in the woods or prairie, look at the snow for small depressions, holes, and feather markings surrounding the cavities. It’s a sure sign that you’ve come upon a grouses’ roost.
There are numerous examples of wildlife survival and a myriad of unique adaptations they use. Chickadees and nuthatches are able to survive cold winter nights by huddling together with their conspecifics inside natural tree cavities, birdhouses, and woodpecker holes.
Black bears feed on high-protein foods throughout the growing season in order to put on dozens of pounds of fat on their bodies, only to burn most of the stored fat away throughout their long winter slumber — in essence living only on their fat reserves for five or more months.
Animals such as chipmunks, woodchucks, thirteen-lined ground squirrels and other ground squirrels store food in underground burrows, where they eventually retreat to in late summer and early fall. Once safely nestled in their grass-lined sleeping chambers, they enter deep states of true hibernation. Their heart rates slow down, body temperatures drop, and metabolic needs are greatly reduced.
Wildlife survival in extreme conditions is a fascinating topic to study and observe. We see it every day: from birds at our feeders flying away with seeds that they cache to eat later, to tree squirrels that hole up inside wood duck houses or woodpecker holes during a blizzard, wildlife everywhere are surviving and thriving, as we get out and enjoy the great outdoors.