Take Me Outside: The Role of Snow
Posted: 02/12/2022 19:08:00
Modified: 02/12/2022 19:06:07
Mention snow and you’ll likely get a wide range of reactions. Some people love it for the outdoor sports it makes possible. Others are content to enjoy the beauty of snow-capped trees, a sparkling hillside or wind-carved snowdrifts. Still, some people complain about having to shovel, blow snow, or otherwise move or drive through it. If our wild neighbors had opinions, they would also be varied. Snow is essential to the survival of some and a huge obstacle for others.
Many creatures take advantage of snow as a protective layer. Dry, fluffy snow is usually 90-95% air, trapped in frozen water. This provides very effective insulation. Temperatures at ground level or inside a snow bank can often be 40 to 50 degrees warmer than the air temperature, and there is no wind to make it even colder . It can mean the difference between survival and death for many small mammals.
Exit and entry holes are a clue to subnivial (under the snow) activity, but evidence is more readily visible when the snow begins to melt and the once-hidden tunnels of meadow voles, shrews and mice become more visible.
The ruffed grouse (also known as the partridge) can dive into fluffy snow at least 10 inches deep and spend the night surrounded by a white blanket. Spending time under the snow is not only warmer, but provides some protection from predators.
The density of snow has a lot to do with its degree of protection. If the snow is wet and heavy, the insulation properties are greatly reduced because the air gaps are filled with water. If the temperature drops significantly and the wet snow freezes, it is difficult for burrowing animals to cross it or for grouse to dive into it. In these cases, animals must find alternative shelters that are not as warm or protected and may contribute to higher winter mortality.
However, more solid snow can benefit animals that stay above the white stuff. The snowshoe hare’s large hind legs allow this timber lagomorph to practically float on snow when it’s fluffy, but especially when the surface is more solid. Unfortunately, it may also be easier for a coyote chasing the hare to run through the snow in search of a meal. This is when the hare’s white winter fur is especially useful. Standing still and blending into the snow is another way the snowshoe hare enjoys a whitewashed landscape.
Other local mammals that bleach in the winter to take advantage of the snow cover are the short-tailed and long-tailed weasels. Camouflage helps them pursue their prey undetected, but also makes them less visible to large mammals and predatory birds that are also desperately trying to survive the winter.
Some predators have amazing adaptations that overcome the challenges of snow cover. The acute hearing abilities of foxes, coyotes and owls allow them to hear their prey dashing through tunnels under the snow. Unless there is a hard crust on the surface, they are able to break through the snow, crush the tunnel, or leap directly into it.
For other creatures, the snow can present great difficulties. White-tailed deer in particular struggle when there is deep snow. Even if there is a scab, the deer are likely to break through, expending additional energy with each step. This is why you often see deer tracks in single file, saving energy by walking where the snow has already been trampled. Deer also congregate under evergreen trees where the snow is not as deep and form spots called “deer yards”.
Turkeys and squirrels that rely on buried acorns and seeds may struggle to find food if the snow is deep. At such times, they may switch to different foods such as tree buds, evergreen ferns, and tree mushrooms.
As climate change alters weather patterns and the types and amounts of snow we receive, wildlife and humans will need to adapt. It will clearly be easier for some of us than for others, depending on our relationship to the snow.