Wood mice eat seeds, green plants, fruits and animal foods. In a mixed deciduous woodland they eat acorns and sycamore seeds for most of the winter, buds in early spring, caterpillars, worms and centipedes in early summer and blackberries and fungi in the autumn. Food is cached in underground burrows. Food remains are found in disused bird nests, on tree stumps and in sheltered feeding places between the roots of trees or under ledges. They tend to leave the flesh of fruit and eat only the pips.
Most wood mice live in underground burrows.
The burrows are fairly complicated and may include nest chambers and food stores. Burrows probably survive from one generation to the next and will be enlarged or modified as required. Nests are commonly made of leaves, moss and grass. They are usually built below ground under the roots of shrubs or trees but occasionally are found in holes in trees, buildings and bird or dormouse nest boxes. Additional nesting material is used in autumn and winter and often the mouse blocks the entrance to the burrow with leaves, twigs or stones.