In early summer at our place, we host many Eastern Chipmunks, indoors (garage, woodshed, cellar) and out (low branches, flower gardens, stone walls, compost, and forest edges). And every morning, on my walk on back roads and woodland trails with Jessie the chipmunk chaser, the chippies warn of our presence.
Their “chuck, chuck, chucks” and sharp “chips and trills” can be easily mistaken as bird calls. They taunt Jessie the dog, who dashes after them along stone walls, brush piles, and the edges of fields, where the chipmunks can disappear into wall crevices, hollow logs, and their subterranean dwellings.
The Eastern Chipmunk (Tamias minimus) is the only Tamias species in New England, but up to 20 chipmunk species inhabit the western states and provinces. Our chipmunks are perhaps the most charming squirrels in eastern hardwood habitats. They may also be the most abundant (our neighbor has counted 27 on her place). Their rusty-colored coats are accented from the neck along the length of the back with five dark brown stripes alternating with white stripes. Similar stripes run from the tip of the nose across the eyes and cheeks and past the ears. Posing in a cute and charming posture, a chipmunk will sit up on its haunches with its ears and eyes alert and its gray tail flicking.
Through the course of a year, we can expect to see chipmunks from February through June and again from Labor Day to Thanksgiving. However, in winter and late summer, Eastern Chipmunks move into their dens. These underground dwellings are a complex of tunnels, storage chambers, and insulating nests. In winter chipmunks may move to the surface and tunnel through the snow from their den to sources of subnivean sunflower seeds, corn, beechnuts, acorn, and other tree seeds. But most seed gathering and storing takes place in the fall, and when stowed away in their pantry the seed will nourish the chipmunk family through the winter. A chipmunk gathers these hard mast foods with its own built-in shopping bags – those elastic cheeks that may hold up to 30 shelled beech nuts at a time. In spring and early summer, the chipmunk menu includes mushrooms; tubers, bulbs, and fruits; ground-nesting bird eggs; and invertebrates such as worms, grubs, beetles, and other delectable items.
Chipmunks are seldom seen in late summer for more than one reason. Preferred foods are less available late in the season, and a second litter of helpless young may be born in the den. Hungry predators of small mammals are numerous in summer: hawks and owls, foxes and coyotes, bobcats, weasels, raccoons, as well as domestic dogs and, especially, cats. All our squirrel species, including chipmunks and woodchucks, are capable of climbing trees to escape terrestrial predators. Generations of country children have believed in “snake holes!” - small holes 1-2 inches wide in the soil. Of course, snakes don’t have digging tools, but they can move into holes, crevices, and dens in search of prey. In the Kingdom, only the Eastern Garter Snake might glide into the hole of a chipmunk den for lunch or shelter.
Even chipmunks are seldom the architects of their own dwellings; they lack the digging tools that moles possess. The chipmunk den may be a remodeling of a mole’s tunnel system, or decayed root systems, hollow logs, or other soil cavities. The completed remodeling includes storage spaces, “pantries” stocked in food supplies, nest spaces lined with soft leaves or other vegetation, passageways with at least two entrances, and drain tunnels to avoid drowning. Depth of the den system may approach 3-4 feet. In winter, the chipmunks feed on stored plant materials, but they also spend spells of torpor in which they reduce their metabolism to inactivity and save the stored nutrients.
Chipmunks are very numerous and widespread in deciduous forests when resources are plentiful; such conditions induce active reproduction. Each litter produces up to nine young, all blind and without fur for a month before emerging from the nest. Some females may have two litters, one in spring and another in mid- to late-summer. Life expectancy for adult chipmunks is 2-3 years. The math points toward a large, sustainable chipmunk population. They operate with a keen sense of smell, lightning quick reflexes (the ones that trigger workouts with Jessie), well-evolved social interactions with vocal and behavioral communications, and an active curiosity.
The media have defined chipmunks as cute, funny, brash, and musical. Disney’s Chip and Dale characters in cartoons and comic books, and the high-pitched comical songsters Alvin and the Chipmunks, have outlasted more than two human generations. Watching your neighborhood chippies with amusement and delight will tend to confirm those characters!
Special thanks to the Adirondack Ecological Center. For more detail about Eastern Chipmunks go to their website: https://www.esf.edu/aec/adks/mammals/chipmunk.htm