The deep snow pack that formed this winter and its persistence in remaining has created hardships for many forms of wildlife, yet a few creatures have benefited from this substantial crystalline covering, especially the mice.
Life for a small, ground dwelling rodent in winter is a challenge that many individuals fail to survive. Not only must a mouse find enough to eat in order to maintain an internal temperature near 100 degrees, but it must also avoid the many predators that target this round-eared critter. After most other small creatures, like the chipmunk, wood frog, jumping mice, salamanders and snakes have entered their dormant stage in autumn, only a few ground dwelling forms of prey remain active for our carnivores to hunt. This substantially increases the pressure on these familiar small rodents.
In their attempt to avoid being seen by a fox, coyote, bobcat, fisher, hawk, owl or other meat eater, those mice that have not taken up residence indoors tend to confine their travels as much as possible to places under the snow’s surface. Limiting their foraging activities as much as possible to the crevices and hollows under fallen logs, around large rocks and stumps, and beneath other objects on the forest floor helps to conceal these critters from the view of the larger animals that are always on the prowl for prey.
While the keen senses of hearing and smell of most predators, especially the fox and coyote enable these highly perceptive animals to detect the movements of a mouse under the snow, their ability to capture one depends on the depth of the snow, as well as surface conditions. Rapidly and accurately digging through more than a foot of powder becomes a major challenge for any quadruped. The noise generated in flinging aside the snow instantly alerts the quarry to an attack, and causes this potential meal to quickly retreat from that spot. Unless a predator attacks with lightning speed, it will never be successful in apprehending a roving mouse beneath the snow pack.
A crust on the surface presents an even more formidable barrier to snagging a mouse as it moves in the shallow spaces that exist between the forest floor and the snow that covers the ground. A dense crust which forms after a late winter thaw is especially beneficial, as it can act like a coat of armor over the domain of a mouse.
Hawks and owls are particularly adversely impacted by the presence of a substantial layer of snow throughout the winter. These hunters rely entirely on snatching creatures that are traveling on top of the snow, or are moving just below the surface. While their razor sharp talons are effective weapons in quickly killing prey, they are useless in digging through the snow to search for an animal that has recently burrowed down into the powder to escape an attack.
Aside from offering protection from its numerous natural enemies, snow also provides mice with protection against bitter cold temperatures. Snow is an excellent insulator, and a layer of fluffy powder effectively traps the heat contained within the soil, making a far more favorable microclimate beneath this seasonal blanket than the air above.
It is difficult to say when the snow will eventually disappear for the season. For outdoor enthusiasts that enjoy bare ground and for the region’s numerous predators, it can’t come soon enough. But for the mice, a snow pack that lingers well into April is ideal, for this is when the intensity of the sun’s rays begins to thaw the soil and awakens most dormant critters. As these creatures begin to repopulate the forest floor, in an often still lethargic state, the appetite of the predator community begins to become satisfied, and hunting pressure eases on the mice.
So far, this has been a near perfect snow season for our mouse community, and undoubtedly, there are now plenty of mice to begin their extensive breeding season. With their normally high rate of reproduction, it can be expected that there will be an over abundance of these small, ubiquitous rodents by the time mid autumn arrives, and countless individuals will be looking for a warm home in which to spend next winter.