Ground squirrels are burrowing rodents often considered property pests. These social animals live in extensive underground colonies, which is the primary source of property damage. The nature of their burrowing and feeding habits means they pose a significant threat to structural integrity, landscaping investments, and utility systems. This article explores the specific ways ground squirrels cause destruction and outlines practical methods for managing their populations.
Distinguishing Ground Squirrels From Other Rodents
Ground squirrels are often confused with their arboreal relatives, the tree squirrels, or other tunneling pests like gophers and chipmunks. Ground squirrels live primarily in complex, multi-entrance burrows rather than nesting above ground. They are diurnal, meaning they are active during the day, which makes them visible as they forage and stand guard near their burrow entrances.
Physically, ground squirrels typically have earth-toned fur with mottling or faint stripes, and a moderately bushy tail. Their burrow entrances are distinct, presenting as clean, open, and round holes, usually 2 to 4 inches in diameter, often with a crescent-shaped fan of excavated soil nearby.
The colonial and burrowing nature of ground squirrels is the root cause of their destructive potential. A single colony can develop an interconnected network of tunnels that destabilizes the soil over a wide area. This behavior, rather than climbing or gnawing within structures, is the reason they are considered a unique threat to property.
Property Damage Caused by Extensive Burrowing
The primary structural threat from ground squirrels comes from their habit of excavating extensive underground tunnel systems. These burrow networks can weaken the soil beneath hardscape features like concrete foundations, patios, sidewalks, and retaining walls. The removal of soil creates voids that can lead to soil subsidence, causing the structure above to settle, crack, or collapse.
Ground squirrels frequently burrow along utility paths. Their tunneling activity can inadvertently damage or sever buried irrigation lines, water pipes, and underground utility cables. Additionally, ground squirrels often gnaw on plastic components, such as sprinkler heads and drip irrigation tubing, to access water.
The excavated dirt from their burrows creates large mounds on the surface that can increase the risk of soil erosion. Unstable tunnel systems can also collapse, creating sunken spots in lawns or fields that pose a tripping hazard for people and equipment.
Risks to Gardens and Landscape Investments
Ground squirrels are voracious foragers that directly impact gardens and ornamental landscaping. Their diet includes a wide variety of plant material, meaning they consume vegetables, fruits, seeds, and flower bulbs. Newly planted seedlings are particularly vulnerable, as ground squirrels will devour young plants in their earliest stages of growth.
Ground squirrels use their incisor teeth to gnaw on the bark of young shrubs, vines, and trees. When this gnawing encircles the trunk, known as girdling, it can kill the plant by interrupting the flow of nutrients and water. Their digging around plant roots to forage also causes plants to wilt or become stunted.
The surface activity of ground squirrels also ruins turfgrass and garden beds. They create numerous holes and mounds of displaced soil across a lawn, which can smother the surrounding grass. Their habit of caching food supplies in shallow holes results in localized damage as they dig up seeds and bulbs for storage.
Methods for Managing Ground Squirrel Populations
Managing ground squirrel populations requires an integrated approach that begins with making the property less hospitable to them.
Habitat Modification
Habitat modification involves removing sources of shelter and food, such as clearing brush piles, rock piles, and debris that provide cover. Cleaning up fallen fruits, nuts, and birdseed can reduce the attractiveness of a yard as a feeding ground.
Exclusion Techniques
Exclusion techniques create physical barriers to protect vulnerable areas and structures. This involves burying heavy-gauge wire mesh or hardware cloth at least two feet deep around foundations or garden perimeters to prevent burrowing access. A two-foot-wide gravel barrier using large, one-inch diameter stones can discourage burrowing near concrete slabs.
Direct Control Methods
For established infestations, direct control methods may be necessary, including trapping, fumigation, or the use of rodenticides. Trapping is effective for small populations. Burrow fumigation uses toxic gases to eliminate squirrels within their tunnel systems, but this method is most effective when the soil is moist and must never be used near buildings due to safety risks. Property owners must check and strictly adhere to all local, state, and federal regulations regarding pesticide application.