RUFOUS TREE MOUSE
Phenacomys longicaudus
In their native haunts these mice have habits varying with varying conditions. On brushy plains they burrow in the ground, while in the woods they sometimes burrow under rocks, stumps, and logs, or live in hollows in stumps and trees. As nimble in climbing as squirrels, many live in hollow trees sometimes more than fifty feet above the ground.
That our inability to see at night prevents more than an occasional glimpse at the doings of the small animals which often swarm all about us was impressed on me at one of my camps in the desert of Lower California. My blankets were spread under a small leafless tree growing near the base of a rocky ledge, in the crevices of which many relatives of the white-footed mice were living. The first morning in camp I awoke as the sky began to pale and color with the approach of day. The dry branches of the tree a few feet overhead became sharply silhouetted against the sky, revealing several of the mice running up and down them and leaping from twig to twig with all the active grace of tiny squirrels.
The mice appeared to be racing about in pure playful enjoyment of the exercise, and when the light had increased sufficiently to render objects on the ground distinct they suddenly ran down the tree trunk and vanished in a crevice in the rocks. This game was repeated on several succeeding mornings and is no doubt commonly indulged in where conditions are favorable.
White-footed mice feed mainly on many kinds of seeds and nuts and vary this diet with snails, insects, and sometimes with the flesh of dead birds or other mice. As they do not hibernate they lay up abundant stores of grain and seeds of many kinds in addition to a variety of nuts, as acorns, beech nuts, pine nuts, maple seeds, and others, according to the locality. The stores are hidden in hollows in logs, stumps, trees, or in the ground. When in captivity they have shown themselves expert in catching flies, sometimes capturing them with their teeth and again with their front paws used with all the dexterity of little hands.
Several litters of young containing from three to seven each are born, the first usually appearing in spring and the last in fall. The young are blind and helpless at birth, and in this condition cling so tenaciously to the mother’s teats that when she is frightened from the nest they are often carried off attached to her.
Some individuals at least of the white-footed mice, like others of the genus Peromyscus, are known to have a prolonged and musical song. It is a fine warbling ditty, a little like the song of a canary. A number of good observers have recorded these performances, but they appear to be so infrequent that most people with woodland experience have never heard them.
The lives of these mice are passed in constant fear of a host of enemies. Hawks and owls, bluejays, and shrikes in the bird world are ever on the alert to capture them, while skunks, weasels, minks, foxes, and snakes persistently seek them in their retreats.