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Fifteen species of native chipmunks of the genus Eutamias and one of the genus Tamias are found in North America. The eastern chipmunk (Tamias striatus) and the least chipmunk (Eutamias minimas), discussed here, are the two most widely distributed and notable species. Behavior and damage is similar among all species of native chipmunks. Therefore, damage control recommendations are similar for all species.
The eastern chipmunk is a small, brownish, ground-dwelling squirrel. It is typically 5 to 6 inches (13 to 15 cm) long and weighs about 3 ounces (90 g). It has two tan and five blackish longitudinal stripes on its back, and two tan and two brownish stripes on each side of its face. The longitudinal stripes end at the reddish rump. The tail is 3 to 4 inches (8 to 10 cm) long and hairy, but it is not bushy.
The least chipmunk is the smallest of the chipmunks. It is typically 3 2/3 to 4 1/2 inches (9 to 11 cm) long and weighs 1 to 2 ounces (35 to 70 g). The color varies from a faint yellowish gray with tawny dark stripes (Badlands, South Dakota) to a grayish tawny brown with black stripes (Wisconsin and Michigan). The stripes, however, continue to the base of the tail on all least chipmunks.
Chipmunks are often confused with thirteen-lined ground squirrels (Spermophilus tridecemlineatus), also called “striped gophers,” and red squirrels (Tamiasciurus hudsonicus). The thirteen-lined ground squirrel is yellowish, lacks the facial stripes, and its tail is not as hairy as the chipmunk’s. As this squirrel’s name implies, it has 13 stripes extending from the shoulder to the tail on each side and on its back. When startled, a ground squirrel carries its tail horizontally along the ground; the chipmunk carries its tail upright. The thirteen-lined ground squirrel’s call sounds like a highpitched squeak, whereas chipmunks have a rather sharp “chuck-chuckchuck” call. The red squirrel is very vocal and has a high-pitched chatter. It is larger than the chipmunk, has a bushier tail and lacks the longitudinal stripes of the chipmunk. Red squirrels spend a great deal of time in trees, while chipmunks spend most of their time on the ground, although they can climb trees. Range: The eastern chipmunk’s range includes most of the eastern United States. The least chipmunk’s range includes most of Canada, the US Rocky Mountains, the Great Basin, and parts of the upper Midwest.
Exclusion: Rodent-proof construction will exclude chipmunks from structures. Use 1/4-inch (0.6-cm) mesh hardware cloth to exclude chipmunks from gardens and flower beds.
Habitat Modification: Store food items, such as bird seed and dog food, in rodent-proof containers. Ground covers, shrubs, and wood piles should not be located adjacent to structure foundations.
Frightening: Not effective.
Repellents: Area repellents. Naphthalene (moth flakes or moth balls) may be effective if liberally applied in confined places.
Taste repellents: Repellents containing bitrex, thiram, or ammonium soaps of higher fatty acids applied to flower bulbs, seeds, and vegetation (not for human consumption) may control feeding damage.
Toxicants: None are federally registered. Check with local extension agents or a USDA-APHIS-ADC personnel for possible Special Local Needs 24(c) registrations.
Fumigants: Generally impractical.
Trapping: Rat-sized snap traps. Live (box or cage) traps. Glue boards.
Shooting: Small gauge shotguns or .22-caliber rifles.