New Hampshire Nature Notes
by Eric Orff

Life below the winter snow, entering the depths of winter.

Wednesday 01/20/2010

As I gaze out my home office frost fringed window my mind can't help but wonder what really lies within my grand view of things mostly unseen. The snows of the last two days has covered all that can be seen in a blanket of white. All looks quiet, peaceful and in a state of torpor for the balance of the winter. Yet I know under the snow covered white ice of the Suncook River life goes on for the fishes there. How do they survive in this near freezing water I wonder? Are they tucked away in some eddy riding out the winters currents? And just beyond the river in a slack water tributary coated with a thick layer of mud, I call the meadow, I imagine perhaps some frogs tucked in for the winter turning as brown as the muck.

And shrouding the meadow are thick stands of grasses and shrubs, suitable cover, blanketed by the cover of snow, and beyond to the gem green forest. It is there I imagine life goes on.

Here it is, almost February -- the month we know as "the dead of winter." It will be months before life is resurrected from the bleakness of New Hampshire's snow-covered landscape. In reality, though, there is no "dead" of winter -- lots of life exists just beyond our eyesight. It's called subnivean life. Life UNDER the snow. Mice, voles, shrews -- and the predators that search for them, like weasels and shrews, live a subnivean life for months under the snow cover.

Oh what a life they lead! While temperatures may dip to 10 or even 20 degrees below zero, and a sharp winter wind can add an almost immeasurable chill, subnivean life is warm and snug. Water vapor condenses under the snow's surface, freezes and seals out the chilly outside air. Typically, temperatures are just above freezing in a creature's winter lair under the snow, sometimes 50 degrees warmer than the night air outside.

In their tunnels under the drifts, mice and voles dine on nuts, seeds, grass and bark, for the most part hidden from prying eyes of predators like foxes, coyotes and owls. The little creatures create multiple burrows under the snow, leading to food supplies. Often, routes travel along dead and down woody debris lying on the forest floor under the snow.

Some predators have learned to hunt for these munchy morsels by listening and pouncing into the snow to capture them. Still, for nearly half the year, mice and voles find heavenly habitat sequestered beneath the snow in their subnivean world. So don't think of February's blanket of snow as a casket for the dead of winter, but as a warm, protective comforter for a universe of winter wildlife.