Kevin Pugh, Wildlife Biologist, Alabama Division of Wildlife and Freshwater Fisheries
You are sitting on your porch enjoying a late summer sunset, or maybe an early morning sunrise, when the silence is interrupted by a rather sharp “chuck-chuck-chuck” sound coming from the shrubbery. Not seeing anything and unsure of what it is, you dismiss the sound from your mind. A few days later you notice the bird seed disappearing from the bird feeder at a higher than normal rate, or maybe a small hole has appeared at the edge of the patio. That evening, as you walk out on the porch, you catch a glimpse of a reddish-brown flash as it disappears into a hole. Congratulations, you now have a new resident commonly known as a chipmunk. Despite the cartoon and movie depictions, chipmunks do not make good guests.
The Eastern chipmunk is a small, reddish-brown, ground-dwelling squirrel. It is typically 5 or 6 inches long and weighs about 3 ounces. It has two tan and five black stripes on its back, and two tan and two brownish stripes on each side of its face. The tail is 3 to 4 inches long. When startled, it makes a hasty retreat with its tail straight up in the air. Although they can climb trees, chipmunks spend most of their time on the ground.
Eastern chipmunks typically inhabit woodlands and woodlot edges, but they also inhabit areas in and around homes. They are most active during the early morning and late afternoon. Burrows are usually well hidden in woodpiles, near stumps or brush piles or around the edges of buildings. The chipmunk also disguises its burrow entrance by carrying the dirt away in its cheek pouches and scattering it away from the burrow, making the burrow entrance less conspicuous. The main burrow tunnel is normally 20 to 30 feet long but, where cover is sparse, chipmunks may excavate complex burrow systems. The burrow system usually consists of a nesting chamber, one or two food storage chambers, various side pockets connected to the main tunnel, and separate escape tunnels. During cold weather, chipmunks enter a restless hibernation and are relatively inactive. They don’t enter a deep hibernation, but rely on the cache of food they previously brought to the burrow. On warmer winter days, they may also be observed scurrying actively above ground. Most chipmunks emerge from hibernation in early March.
Chipmunks generally have two litters a year with two to five young born in the spring and again in later summer or early fall. The young appear above ground when they are four to six weeks old. They will leave the burrow at six to eight weeks of age and reach sexual maturity within a year. The life span of an adult chipmunk is usually about three years.
Chipmunks feed primarily on grains, nuts, berries, seeds, mushrooms, insects and carrion. They may also occasionally prey on young birds and bird eggs. Although they feed mostly on the ground, they will climb trees in the fall to gather nuts, fruits and seeds. Chipmunks store food in their burrows throughout the year.
Although chipmunks are considered minor agricultural pests, most conflicts with chipmunks are nuisance in nature. When present in larger numbers, they can cause structural damage by burrowing under patios, walls or foundations. They may also consume flower bulbs, seeds, or seedlings, as well as bird seed, grass seed and pet food.
Chipmunks should be excluded from buildings wherever possible by using hardware cloth, caulking, or other appropriate materials to close openings where they could gain entry. Hardware cloth may also be used to exclude chipmunks from flower beds. Seeds and bulbs can be covered with hardware cloth with the cloth extending at least one foot past each margin of the planting. Where high populations of chipmunks exist, exclusion is less expensive in the long run than trapping.
Other things to consider when protecting against chipmunk damage are to remove wood piles and debris next to building foundations. Landscaping features such as ground cover, trees and shrubs should not be planted in continuous fashion connecting wooded areas with home foundations. Bird feeders should also be placed at least 15 to 30 feet away from buildings so spilled bird seed does not attract and support chipmunk populations near the building.
Once chipmunks have taken up residence, trapping is the most practical method of eliminating the unwanted pests. Live traps can be baited using peanut butter, seeds or cereal grains. Place the trap along the paths where chipmunks have been seen. Pre-baiting the trap for two or three days will help condition chipmunks to associate the trap with a free food source. Only set the trap after chipmunks are actively feeding on the bait in and around the trap. Check traps frequently to remove captured chipmunks and any non-target animals. Live-trapped chipmunks should be transported and released several miles from the point of capture in an area where they will not bother anyone else. Common rat traps can be used to get rid of chipmunks if these traps are isolated from children, pets and other wildlife. To avoid killing songbirds in rat traps, place the traps under a small box with openings that allow only chipmunks to have access to the baited traps.
Although chipmunks are often considered cute and are definitely entertaining to watch, they make very poor guests. Their consumption of seeds, flower bulbs, fruits and vegetables is annoying at best. Chipmunks can be also be very destructive when it comes to burrowing activities around structures and may even compromise the structural integrity of stairs, patios and foundations. Always remember, exclusion is much cheaper than eradication.