Mention snow and you will likely receive 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 covered trees, a sparkling hillside or drifts sculpted by the wind. Still some people grumble about having to shovel, snow blow or otherwise move it or navigate through it. If our wild neighbors have opinions, they would be as varied. Snow is essential for the survival of some and a huge hindrance to others.
Numerous creatures take advantage of snow as a protective layer. Dry and fluffy snow is typically 90- 95% air, trapped within the frozen water. That provides very affective insulation. Temperatures at the ground level or inside a snow bank can often be 40-50 degrees warmer than the air temperature, and there is no wind to make it feel even colder. That can mean the difference between survival and death for many small mammals.
Exit and entrance holes are one clue to subnivial (beneath the snow) activity, but evidence is more easily seen as 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 a partridge) may dive into fluffy snow that is at least 10” deep and spend the night surrounded by a white blanket. Spending time beneath the snow is not only warmer, but provides some protection from predators.
The density of the snow has a great deal to do with how protective it is. If the snow is wet and heavy, the insulation properties are greatly diminished because the air spaces are filled with water. If temperature drops significantly and the wet snow freezes solid, it is difficult for the burrowing animals to get through it or for the grouse to dive into it. In these cases the animals must find alternative shelter which are not as warm or protected and can contribute to higher winter mortality.
However, more solid snow can be beneficial to animals that stay on top of the white stuff. The large back feet of the snowshoe hare make it easy for this woodland lagomorph to practically float across the snow when it’s fluffy, but especially when the surface is more solid. Unfortunately it might also be easier for a coyote that is pursuing the hare to run across the snow in pursuit of a meal. That’s when the hare’s white winter fur is especially helpful. Sitting still and blending in with snow is another way that the snowshoe hare benefit from a whitened landscape.
Other local mammals that turn white in the winter to take advantage of snow cover are the short and long-tailed weasels. Camouflage helps them pursue their prey without being detected, but also makes them less visible to the larger mammals and predatory birds that are also trying desperately to survive the winter.
Some predators have amazing adaptations that overcome the challenges of the snow cover. The keen auditory abilities of foxes, coyotes and owls enable them to hear their prey scurrying through tunnels beneath the snow. Unless there is a hard crust on the surface they are able to break through the snow, crush the tunnel or directly pounce on them.
For other creatures, snow may present a great hardship. White-tailed deer in particular struggle when there is deep snow. Even if there is a crust, deer likely break through, expending extra energy with each step. This is why you often see deer tracks in a single file, conserving energy by walking where the snow has already been tread on. Deer also gather under evergreen trees where the snow is not as deep and form places called “deer yards.”
Turkeys and squirrels that rely on buried acorns and seeds may struggle to find food if the snow is deep. At times like that they can switch to different foods such as tree buds, evergreen ferns and tree mushrooms.
As climate change brings changes to weather patterns and the types and amount of snow we receive, both wildlife and people will need to adapt. This will clearly be easier for some of us than for others, depending on our relationship with snow.