Townsend's chipmunk hibernates in regions where the winter is harsh, but in other parts of its range that have a more mild climate it can be active year-round. It is omnivorous, eating a variety of plants and insects and even birds' eggs. Townsend's chipmunks in the Oregon Coast Range have higher population densities in areas with dense shrubbery, especially salal (Gaultheria shallon). In the summer and early fall, Townsend's chipmunks eat blackberries, salal berries, and thimble berries. In the late fall, they eat acorns, huckleberries, maple seeds, thistle seeds, grain seeds, grass, roots, and conifer seeds.