Nature Tracks
Dens and Dreys –Bears and Squirrels Nestled in for Winter
Treetops jostle. Snow twisters whip up and dance away. Snow skitters across the flats like smoke. This cold and blustery January day requires refuge. I’m here in a heated home, but how are our wild creatures faring out there in wind chills dipping into the negative numbers? Need I be concerned? Where are they?
The grey squirrel is active all winter, except on cold days like this. On such days, he can be found high in a tree. There he has made a drey, or nest out of twigs and deciduous leaves in the fork of sturdy branches. He may have bunkmates for extra body warmth or he may go it alone. Lined perhaps with soft grass, the squirrel lies curled up with his bushy tail wrapped around him like a blanket. On a day not quite so harsh, he’ll climb down and search for a buried nut or two to snack on, and then retire again to his winter abode. His summer house may be higher up, between branches that sway in the wind on such days as this. These dreys are easily seen now that the leaves are no longer hiding them. If the squirrel has made a sturdy drey packed with lots of insulating leaves, has a decent layer of fat and a thick winter coat, he should make out just fine.
Black bears don’t hibernate either. They’re too big. A bear has too much body mass to heat up when it comes time to wake in the spring. Body temperature, breathing and heart rate drop dramatically in true hibernators like ground squirrels, jumping mice, and ground hogs. Not so in bears. It is more correct to say black bears are in a state of “carnivorous lethargy”. Let’s just say they’re groggy.
A black bear will most probably stay in a well-chosen den for many weeks at a time. The den-of-choice is a big tree cavity. Pregnant females prefer these sites, which are safest from predators and weather. Otherwise, a den site on the ground will do the job – under a windfall, in a brush pile or in a rock crevice. A cave would not be ideal because there is too much space to heat. A den big enough for a curled-up bear to move around a bit is just right.