Monday, February 2, 2015

Under the snow

By Beth Sullivan
Before the blizzard, while most of local humanity was at the grocery store stocking up, the birds flocked to the bird feeders, scratched the leaves, and pecked under bark looking for every morsel they could find before they took cover. A few species of birds are known to stash food-Blue Jays do it-but most birds just rely on having food available when they need it, bulking up and adding extra fat to see them though. Then they hunker down in a protected site and try to expend as little energy as possible during the bad weather.
In the Fall, hunting is easier but foxes are quite successful despite deep snow. (Photo by Rick Newton.)

Life under the snow

Small mammals will actually thrive under the snow pack. Voles and mice have stored seeds and grains in their burrows since the fall. While most mammals will slow down a bit during the winter, many will remain active, tunneling shallowly under leaves and loose soil. It is not uncommon to see shrews or voles disturbing the soil under birdfeeders, like small earthquakes, as they search for seed remnants or insects. However, even such small movements are very noticeable to predators. But once the snow blankets the ground, they can actually tunnel more freely. They can move between protective hiding places and food sources and usually avoid detection. There are wonderful images of foxes triangulating their senses on an underground burrow, then leaping high and diving head first into the deep snow to catch their prey. I have witnessed it once, and it is truly a wonder to watch. Owls have hearing abilities that allow them to do the same, and while they do not hurl themselves head first into the snow, they can land with spread wings and thrust their talons deeply to latch their target.
One can imagine small creatures hiding in crevasses under the snow.

Dirty snow around the hole indicates the fox is active.

Light snow still allows birds to scratch for food.

When the snow melts in the spring, it is also easy to see trails etched into the grasses and dirt that point out the well-worn paths these creatures have used all winter.
When the snow melts, tell-tale signs of winter tunnels remain.

Winter hotel

This is the time of season when brush piles and tangled hedgerows are their most valuable as refuge for many creatures. The heavy snow catches on upper branches and preserves open areas beneath for hiding. Dense shrubs still living provide an extra bonus. Small mammals will seek living bark and gnaw it for valuable sustenance. However, the longer the snow is on the ground, the longer they have to gnaw, and when spring arrives, stems have been girdled, and the branch will die. Under the bark of trees, insects remain, some in a suspended state, some as larva, and some as eggs, but available as food for birds, if above the snow line, and for shews under the snow.
Brush piles, natural or man made provide vial cover for mammals and birds.
Stonewalls offer cover for small animals and hunting places for predators.

The deeper snow cover also offers insulation. Hard to believe but the snow pack remains warmer, closer to thirty two degrees, freezing, while the air above may have temperatures plummeting to zero. Plants survive bitter winters much better when there is a constant snow cover.
This stem was buried under snow for an extended period, and shows the teeth marks of a gnawing mammal.

Whether you observe from a window or strap on snowshoes and get out into the snow, take some time to think about what is happening below the drifts. Think of all the wonderful adaptations wildlife has to survive in the places we preserve for them.

Photographs by Beth Sullivan unless indicated.

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