Under the Blankets

by Jan Hudson Krueger

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The snow of last week lies on the land like one of Grandma's white chenille bedspreads. There might be a few tracks making patterns on its surface and some clumps that have fallen from the black-green branches of spruce, pine and balsam trees. The wan winter sunlight throws long pale shadows across it from the dormant maples, ash, poplars and birches and an occasional chickadee, blue jay or crow may dart past your vision. Otherwise, it all looks like a quiet, serene but lifeless tableau.

But under that blanket, it is anything but lifeless. True, many plants and insects have perished in the first frost, but their seeds and eggs lie under the litterfall, waiting for spring to sprout or hatch. Life thrives when the snow layer is thick enough.

A useful phrase to explain the survival strategies of animals native to our biome is "migrate, hibernate or insulate." The songbirds, hummingbirds and Monarch butterflies have long since fled to warmer climes. Reptiles, amphibians and a few mammals such as chipmunks have tucked themselves away, sleeping a perilously death-like slumber, oblivious to the killing chill. Everybody else has followed the last rule, and have constructed warm dens, lined with fur for better insulation and are most active in their quest for food.

"The subnivean zone is the area between the surface of the ground and the bottom of the snowpack. The word subnivean comes from the Latin “sub” (under) and “nives” (snow). Mice, voles, and shrews retreat here for protection from cold temperatures, bitter winds, and hungry predators. Food is right at hand: grass, leaves, bark, seeds, and insects are free and unfrozen. Under the snow, these tiny mammals create long tunnel systems complete with air shafts to the surface above." (The Adirondack Almanac)

The tunneling system can be quite intricate and extensive, especially when the snow cover is fairly deep. "In this subnivean space...some rodents live more communally, clustering in dens for warmth, excavating latrine caves to isolate the scent of their feces and urine from their living 

quarters. When small mammals do surface -sometimes to seek new food sources - they ascend and descend the snowpack in tunnels where radiant heat has thawed the snow along tree trunks and shrubs." (Audubon magazine)

But it is not foolproof protection. One of the more fascinating videos I have seen was of a fox, bending its head to listen for the faint rustling noises of rodents running along unawares in their tunnels below the snow. Using this method to pinpoint the location of its prey, the fox then leapt straight up into the air, inverted itself and dove, snout-first into the soft snow pack. After two or three times of executing this comical behaviour, it came back up with a mouse, shrew or vole in its jaws.

Owls also hunt by sound. "An ill-timed squeak can bring talons punching from above. On windless mornings when the snow is powdery you sometimes find an impression of owl wings on either side of the hole." (Sudbury Valley Trustees) And a weasel will enter the tunnels and chase down mice et al, using their escape routes against them. It's a good thing that these little mammals reproduce at a prodigious rate!

In addition to all this drama, butterfly chrysalises and cottony moth cocoons hang from low-slung weed stalks, nestle under the duff or lie tucked into deep protective fissures in the tree bark. Mosses, strawberry plants and garlic mustard are just some of the plants that stay bright green under the snow. I guess we can't really call it "the dead of winter" anymore.