The eastern chipmunk (Tamias striatus) is a very common and well-known rodent. It is a forest species, but is also very comfortable living around near people. The chipmunk is a fun to watch as it scampers about; however, if it moves into a house, it can cause considerable damage.
Eastern chipmunks are versatile and can be found in a variety of habitats. Their main habitats are deciduous forests, forest edges and areas of thick brush. They may also be found in meadows, fields and along fence lines. They also frequent bird feeders, gardens, and nut producing trees. Ideal chipmunk habitat will have abundant food supply, cover, and adequate den sites.
Den sites are not usually a problem as chipmunks can burrow into the ground or use holes in hollow trees, logs and stone walls. They will also use spaces under buildings and in houses.
Chipmunks build complex burrow systems with dens, tunnels, and food storage areas often over ten feet in length and three feet in depth. The dens usually have two levels. The upper level is where the chipmunk sleeps and is lined with grass and leaves. The lower level is used for food storage.
Eastern chipmunks are not true hibernators as they are unable to build up a large enough fat reserve to sleep uninterruptedly through the winter. Instead, they wake periodically throughout the winter, usually on warmer days, to feed on stored food or forage above ground.
Chipmunks are generally solitary animals except during the breeding season. They are most active during the day, especially mid-morning and mid-afternoon. Chipmunks are territorial and will aggressively defend their burrow entrance. They vocally threaten and will even chase away intruders approaching their territory.
Eastern chipmunks breed twice a year, once in early spring and then again in July. After a 31 day gestation period, a litter of two to eight young is born in a den underground.
The young are born naked, blind and completely helpless, but grow and develop quickly. By the eighth day of life, their stripes begin to appear. After one month, their eyes open and they have become completely covered with fur. At six-weeks old, they are weaned and leave the burrow for the first time.
The full-grown chipmunks leave their parents den at eight weeks of age. Both the male and female chipmunks reach sexual maturity by the time they are one-year old. Chipmunks can live up to two years in the wild and have been known to live up to eight years in captivity.
The eastern chipmunk spends the majority of its day in search of food. It is an omnivore, feeding on both plants and other animals. Its diet includes slugs, insect larvae, earthworms, snails, and butterflies, and it will occasionally eat frogs, bird eggs, birds and mice. It also feeds on acorns, nuts, leaves, buds, mushrooms, fruits, berries and seeds.
The chipmunk spends the day scurrying from a food source to its den and back again. The den may contain up to a gallon and a half of nuts and seeds. This food supply helps the chipmunk survive winter, when food is scarce. It may stop its single- minded pursuit long enough to eat, and it is common to see them sitting on a stump or stone wall feeding. The chipmunk makes a considerable amount of noise for such a small animal, and you can often hear it feeding from a good distance away.
There is no active plan designed for this species, but continued monitoring is conducted to ensure that their population remains healthy and abundant in Vermont.
Eastern chipmunks are abundant throughout Vermont. Their population size can vary greatly, as it is highly dependent on food availability, such as seeds and nuts, or mast. High winter survival and birth rates are experienced following falls in which abundant nuts were produced.
If food is scarce, however, chipmunk numbers decline. The chipmunk population is a direct reflection of the fall mast productivity.