This is a photo of Monika Halvelka and a White-footed Mouse, during a ramble, at the Koffler Scientific Reserve last week. Monika is a University of Toronto professor and small-animal mammalogist at the UofT's Erindale campus in Mississauga, Ontario. She was a guest lecturer at my Natural History/Docent Training course last week. She stopped at a tree with what appeared to be a bird-box mounted on it, at about chest height. She reached inside and pulled out this groggy little guy. He was in a state of torpor.
White-footed Mice are excellent tree climbers (great swimmers, too). I was surprised to learn they will spend the winter in covered-over, abandoned bird nests, high in hardwood trees, or in tree cavities when they occur. Although they can enter a state of torpor for several hours, they do not go into true hibernation and therefore they cache food in the fall for the winter. The little guy above had stored several acorns into the tree box, from which Monika had pulled him. These tree boxes in the Koffler Scientific Reserve, at Jokers Hill in King Township, are artificial nests which make scientific observation of the mice much easier for researchers and students.
These mice usually eat at night and their diet consists of nuts, seeds, berries, grains, fruits, fungi and insects.
Maybe in another 10 million years, these little creatures will evolve to have wings and they'll fly around in the treetops, as well as nest there. Who knows? We do have flying squirrels, right?