Northland Nature: Cottontails bound over snow
Retired teacher Larry Weber, of Barnum, is the author of “Butterflies of the North Woods" and “Spiders of the North Woods," among other books. Reach him via Katie Rohman at email@example.com.
Two feet of snow on the ground and January’s temperatures can make for a difficult time with the local active winter wildlife. Despite this, the critters are adaptable and they are able to cope with these less-than-pleasant conditions.
Animal tracks in this cold time tell of their activities. Some we will see, such as the diurnal tree squirrels that remain active all winter and frequently come to our feeders for meals. But most of the mammals that are here in January we do not see. Hiding by day, many are about in the cold nights or they live in the subnivean space under the snow.
Digging down through the snowpack, we can find some open space between the snow cover and the ground. This area, called “subnivean,” is present because the Earth generates some heat and the snow is a very good insulator. The geothermal heat produces room between the ground and the snow.
In winter, this becomes a habitat for a number of small wildlife. Mice with short tails, such as meadow mice, voles and shrews may spend a couple months here in relative warmth and safety. The snow’s insulating strength is such that the temperature above the snow may be 30 degrees colder than below.
We usually do not see the subnivean residents, but occasionally mice come above the snow. Here they can hop, but not so beneath the snow. And maybe shrews will leave these protected sites in their quest for prey.
Large mammals like deer and coyotes may have to walk through the deep snow, a formidable task that can be made better with the formation of trails. Such routes make movement easier for them and I find these paths regularly during my walking. Indeed, following deer trails may be a fine way for us to move through the woods in winter.
And then there are those that are small enough that they can move over the snow surface without sinking deeply or at all. Snow conditions vary much throughout the winter, and at times, rather large mammals can stay above on crusty snow.
Lately, I have been seeing the movements of a few kinds of hoppers going over the snow and appear to move about in relative ease. Deer mice (white-footed mice) with their hopping gait are abundant. They are the only hopping mammal that leaves tail marks as it goes.
Other hoppers over the snow include squirrels, weasels (ermine) and snowshoe hare. These are what I have been seeing virtually every day in the present snow scene. And so, it was a pleasant sight to step out for a cold, early-morning walk recently and see the tracks of a cottontail rabbit.
Both the rabbit and its cousin, the hare, are residents in the Northland all winter. When rabbits remain brown, hare change to a white attire. With a white coat and large feet, hare stay in the woods and do fairly well in the winter. The brown cottontails are more likely to be in yards and parks.
Both remain active all winter and usually at night. Both are herbivores and feed on twigs of various plants and shrubs. But both get fed upon as well.
Recently, as I looked out to watch nocturnal flying squirrels on my bird feeder, I saw a barred owl swoop down and snatch one. This could also happen to a cottontail on the nearby ground. The cottontail seen a few days ago will need shelter to survive the tough times of the coming months and may do so.