Chipmunks, though small, can become significant pests due to their extensive burrowing habits. These rodents create complex underground tunnel systems that often undermine sidewalks, patios, retaining walls, and even building foundations, leading to costly structural damage. Their presence is a direct result of readily available food and shelter sources in a yard. Effective control requires a deliberate, multi-step approach. Removing these attractants and implementing physical barriers are necessary steps before considering active removal methods.
Eliminating Attractive Food and Shelter Sources
The initial step in managing a chipmunk population involves making the environment less appealing by removing their primary motivators: food and cover. Chipmunks are omnivorous, but they are particularly drawn to seeds, nuts, and fruits, which they hoard in underground caches for the winter season. Bird feeders are a common source of attraction, as spilled sunflower seeds, corn, and other grains provide an easy, calorie-dense meal.
To mitigate this, bird feeders should be moved at least 15 to 30 feet away from any structure to prevent the animals from being drawn close to the home. Switching to birdseed varieties that chipmunks find less palatable, such as thistle, can also reduce the incentive for them to linger. Any fallen nuts, berries, or fruit from trees and shrubs must be promptly raked up and disposed of to eliminate their natural food supply.
Chipmunks also seek out dense cover for protection and for burrows. Piles of wood, rocks, or yard debris offer ideal hiding spots and often conceal tunnel entrances. Minimizing these obstructions and keeping shrubs trimmed away from the foundation makes the area less hospitable. If firewood must be stored outdoors, stack it away from the foundation to discourage burrowing.
Implementing Physical Barriers and Exclusion
Once attractants are removed, the next phase focuses on physically blocking chipmunks from accessing vulnerable parts of a building or landscape. Exclusion is often the most cost-effective long-term solution, as it prevents new animals from taking up residence. The small size of a chipmunk requires the use of specialized materials to effectively seal entry points.
The most reliable material for blocking access is hardware cloth, a galvanized wire mesh. For chipmunks, the mesh size should be no larger than 1/4 inch, which prevents them from squeezing through gaps. This material should be used to cover foundation gaps, vents, or openings leading into crawl spaces or under decks and porches.
To prevent burrowing underneath structures like patios or retaining walls, the hardware cloth must be buried into the ground in an L-shaped barrier. This involves extending the mesh vertically into the soil for about 6 to 12 inches and then bending the bottom 6 inches outward horizontally, away from the structure. This horizontal flange prevents the chipmunk from digging straight down and under the barrier. For smaller cracks or crevices, materials like copper mesh or stainless steel mesh can be stuffed into the opening before being sealed with caulk.
Safe and Effective Trapping Methods
Trapping is the most practical and effective method for active removal of chipmunks already established in a yard. Small, single-door or two-door live traps are preferred, with mesh openings small enough to ensure the animal cannot escape. Traps should be situated along known travel routes, near den openings, or adjacent to building foundations where activity has been observed.
The best baits are those the chipmunk cannot easily remove without setting off the trap, such as sunflower seeds, nut meats, or a mixture of peanut butter and oatmeal. Spreading peanut butter directly onto the trigger plate works well because the animal must fully enter the trap to reach the treat. To increase success, the trap can be “prebaited” for a few days by securing the doors open, allowing the chipmunk to safely eat the bait and become comfortable with the new object.
Once captured, the trap must be checked frequently, and the chipmunk should be handled while wearing gloves to avoid bites. If choosing to relocate the animal, it is imperative to check local and state wildlife laws, as transporting and releasing captured wildlife is prohibited or heavily regulated in many jurisdictions. If lethal control is necessary, common rat-sized snap traps can be used, baited and placed in active areas, but this is typically reserved as a last resort.