This has certainly been a normal winter so far here in Vermont and New Hampshire – normal in that there’s no such thing as normal. Temperatures have been above average, and snow depth has been below average. Especially in the central Connecticut River valley, which lies north of coastal storms, south of St. Lawrence storms, and lower than the hills on either side, it’s been an almost open winter.
For many of our local animals, winter is the factor that limits their numbers and distribution. A warm and wet winter may lead to a doubling or tripling of some animal populations but a steep decline for others. So, given the warmth and moisture of the winter of ’05-06 so far, who’s up and who’s down?
The shiverers – those animals that basically stand around waiting for warmer weather – are having a field day, of course. Deer are chief among these. Excess calories are a topic of consternation among many humans, but for deer, they mean survival. If the number of calories stored in an animal’s fat is greater than the number of calories required to keep itself warm through the winter, the deer has a good chance of survival. If not, it dies. Simple as that. Very little sustenance comes from the thin browse of winter.
The ruffed grouse is another shiverer benefiting from the warm winter thus far, though for the grouse, the season’s implications are more mixed. The warmth has been helpful, but the thin snow cover has not. Unlike deer, grouse prefer to nestle down into powdery snow where they can take advantage of snow’s insulating value. Particularly if the weather turns sharply colder without snow, grouse will be, quite literally, left out in the cold.
Snow depth plays a more critical role than temperature for the survival of many of our winter regulars. Here again, the deer are benefiting from the skimpy snow. It is still common this January to see deer feeding in fields, around houses, and throughout the woods. In a snowier winter, deer become confined to their “yards,” where the coniferous browse is much less nutritious.
Foxes and coyotes are enjoying a steady diet of moles, voles, and mice this January – more of an autumnal diet than usual. Until the snow deepens, these canines can trot across open fields, triangulating the location of rodents with their acute hearing and pouncing through the snow to secure an easy meal. (Easy in the sense that there is far less risk to life and limb from pouncing on a mole than from trying to drag down a yarded deer, which is more customary deep-snow fare.)
Indeed, it is the rodent clan that has the most to lose from thin snow cover. Ground that may not freeze at all under thick and early snow will freeze now, even though the temperatures are warmer than usual. This makes burrowing difficult and leaves the rodents more exposed to predation from above, and not just from marauding canines. Red-tailed hawks and owls of all stripes are taking advantage of the thin snow cover to continue hunting in woods and fields. Snow’s insulating power isn’t just thermal, it’s acoustic: an owl can hear a rodent through thin snow from 50 feet or more away and swoop down from a nearby branch to make a perfect strike through the scant snowpack.
Snowshoe hare are another species that would just as soon have a deep snowpack, and not just because of their wintry name. Hare rely on deepening snow to reach fresh browse that is otherwise too high to reach from bare ground. The farther they have to travel from home to find fresh browse at ground level, the more likely they are to be spotted by a fox, fisher, or coyote during the commute. Throw in the fact that the hare have turned white for the winter, while some of the ground has remained brown, and the scales are decidedly tipped toward the predators.
The eastern cottontail, on the other hand, benefits from no snow. This rabbit, which was introduced to New England more than a century ago and now inhabits the southern halves of Vermont and New Hampshire, does not turn white in the winter. Nor does it prosper when its preferred burrows – abandoned woodchuck tunnels – fill with snow. A series of less-snowy winters will certainly assist this immigrant in occupying new territory in the otherwise snowy strongholds farther north.
Closer to home, the prospects of our human neighbors are also shifting. Snow-tire salesmen: down. People who heat their houses with expensive oil: up. Skiers, snowboarders, and snowmobilers: down. People who write newspaper articles about what happens in weird winters: way up, especially if it hasn’t snowed and turned cold by the time you read this.