The small, striped eastern chipmunk (Tamias striatus) is a common sight in North American yards, but these rodents quickly become a nuisance when they begin to burrow extensively. Chipmunks create complex tunnel systems that can undermine walkways, patios, foundations, and retaining walls, causing structural damage. Their diet, which includes seeds, nuts, and insects, often leads them to excavate flower bulbs and consume planted seeds, disrupting gardens and landscaping. The goal of managing these pests is to employ effective, humane methods to deter them from sensitive areas, ranging from manufactured sprays to physical barriers.
Commercial and Manufactured Repellents
Commercial repellents trigger a chipmunk’s natural fear response or create an unpleasant sensation. Products utilizing predator urine (e.g., fox or coyote) create a scent barrier suggesting a hunter is present, prompting the chipmunk to leave the treated area. To remain effective, these repellents must be reapplied every few weeks, especially after heavy rainfall, as the scent naturally breaks down.
Strong taste deterrents are another common product category, with capsaicin being the primary active ingredient. Derived from hot peppers, capsaicin binds to pain receptors in mammals, creating an intense burning or irritating sensation when the chipmunk attempts to feed or chew on treated items. This mechanism conditions the animal to associate the protected area, like flower bulbs or foliage, with a negative experience. However, some studies indicate that capsaicin-treated seeds, while effective for squirrels, do not always deter chipmunks from taking the food.
Granular chemical repellents sometimes contain naphthalene, a toxic volatile organic compound registered by the EPA for limited outdoor use around buildings or gardens. Naphthalene releases an odor that animals find unpleasant enough to drive them away. Using mothballs, which contain naphthalene, is often an illegal “off-label” application when used outdoors, as it is only approved for use in sealed containers to control fabric moths. Improper use can pose health risks to people and pets and may contaminate soil and water.
Non-Toxic and Scent-Based Deterrents
Non-toxic repellents rely on strong, concentrated odors or tastes that chipmunks find offensive, making the area less inviting for foraging and burrowing. Essential oils like peppermint, eucalyptus, and cedarwood are frequently used, as their powerful scents irritate the chipmunk’s sensitive nasal passages. A common application method involves soaking cotton balls in pure essential oil and placing them near burrow entrances or in areas of high activity, such as under decks or near foundations.
Household spices and ingredients also serve as irritants. Cayenne pepper or crushed red pepper flakes contain capsaicin and can be sprinkled around plants or mixed with water to create a spray, which the chipmunk may transfer to its eyes and mouth while grooming. Coffee grounds and garlic powder deter chipmunks by introducing strong, foreign odors to the soil. These methods require diligence; scents dissipate quickly after rain or watering, necessitating frequent reapplication.
Physical Exclusion and Habitat Modification
The most reliable, long-term solution for chipmunk deterrence involves physical exclusion and removing environmental attractants. Exclusion prevents chipmunks from reaching areas they intend to damage, such as burrowing under structures or digging up gardens. Hardware cloth, a galvanized wire mesh, is the preferred material for creating barriers due to its durability and small openings.
For effective exclusion, the mesh should have a maximum opening of one-quarter inch to prevent the small rodents from squeezing through. When protecting a foundation, deck, or porch, the hardware cloth must be buried in an L-shape that extends 6 to 12 inches deep and then bends outward horizontally for another foot. This underground apron prevents chipmunks from simply digging under the vertical barrier to gain access.
Modifying the habitat reduces the property’s appeal by eliminating food sources and shelter. Bird feeders are a significant attractant; using catch trays or removing them entirely reduces available food. Promptly clean up fallen nuts, berries, and seeds, and store pet food in sealed containers. Eliminating dense ground cover, minimizing plantings near foundations, and storing firewood away from structures removes potential nesting and cover sites.
Legal Considerations and Removal Methods
If repellents and exclusion fail, physical removal through trapping is the next step, governed by specific regulations. Before setting any trap, individuals must check local and state wildlife laws, as rules regarding the capture, transport, and release of nuisance wildlife vary significantly. Some jurisdictions require a permit for trapping, while others prohibit the relocation of trapped animals to prevent disease spread.
In areas where relocation is illegal, the law may mandate that a trapped animal be released immediately on-site or humanely euthanized. Live-trapping uses small, humane cage traps baited with items like peanut butter or sunflower seeds. Lethal snap traps (mouse-sized) are another option for immediate removal, especially where chipmunks are not a protected species. Consulting a licensed wildlife control operator is advisable to ensure compliance with state and local statutes.