Since they serve as food for so many predators, they need to be prolific and produce a lot of young. Voles are sexually mature at about 32 days of age and, with sufficient food supplies, can breed year-round. With several litters per year, populations can build quickly. Just as quickly, however, local populations may practically disappear. Populations of voles are highly variable from place to place and season to season.
Voles eat a variety of plants, especially grasses and forbs.
In late summer and fall, they gather and store seeds, tubers and bulbs. They also eat the bark of young woody plants. When populations are high, they can eat food crops, especially small grains, and destroy alfalfa fields. Unlike other mice, they almost never enter houses. Though they may look the same, they are not even cousins.