Fig. 3.—Root and trunk of apple tree from Laurel, Md., gnawed by pine mice.
Pine mice feed to some extent outside their burrows, reaching the surface through the small openings made at frequent intervals in the roofs of the tunnels. In their forays they rarely go more than a few feet from these holes. Most of their food is carried under ground, where much is stored for future consumption. While they differ little from meadow mice in general food habits, their surroundings afford them a larger proportion of mast. They are less prolific than meadow mice, but this is more than made up for in the fact that in their underground life they are less exposed to their enemies among birds and mammals. Like meadow mice, they sometimes become abnormally abundant.
In the eastern part of the United States pine mice do more damage to orchards than do meadow mice, partly because their work is undiscovered until trees begin to die. The runs of meadow mice under grass or leaves are easily found and the injury they do to trees is always visible. On the other hand, depredations by pine mice can be found only after digging about the tree and exposing the trunk below the surface. The roots of small trees are often entirely eaten off by pine mice, and pine trees as well as deciduous forest trees, when young, are frequently killed by these animals (fig. 4).
Fig. 4.—Pine tree killed by pine mice.
[DESTROYING FIELD MICE.]
Methods of destroying field mice or holding them in check by trapping and poisoning are equally applicable to meadow mice and pine mice.