Ground squirrels are medium-sized rodents that live primarily on the ground in extensive burrow systems, which distinguishes them from their tree-dwelling relatives. Unlike chipmunks, which are generally smaller and have distinct stripes on their heads, ground squirrels are often larger with less bushy tails, preferring open areas like fields and lawns. These burrowing animals can quickly become a significant problem for property owners and gardeners. They cause widespread damage by undermining hardscaping with their tunnels and consuming valuable plants at the root level. Effective strategies are necessary to protect garden investments from structural damage and crop loss.
Understanding Ground Squirrel Habits
Ground squirrels are diurnal, with peak foraging periods typically occurring in the mid-morning and late afternoon when temperatures are warm and sunny. Their activity is concentrated around their burrows, which serve as shelter, nesting sites, and food storage chambers for their colonies. These complex tunnel systems can extend between five and thirty feet in length and often reach depths of two to four feet below the surface.
Their diet is omnivorous, but it shifts with the seasons, influencing the type of damage they inflict on a garden. In the spring, ground squirrels focus on readily available green forage, such as grasses and herbaceous plants. As the season progresses, they transition to consuming seeds, nuts, fruits, and bulbs, often carrying food in their cheek pouches to cache underground.
Physical Barriers and Exclusion Techniques
Exclusion is a reliable long-term method for safeguarding a garden, as it physically blocks access to vulnerable areas. To create an effective perimeter fence, a heavy-gauge wire mesh, such as galvanized hardware cloth, is necessary. The mesh size should be no larger than one inch by one inch, or ideally half an inch, to prevent smaller or younger squirrels from squeezing through.
A standard fence must be modified using the “L-footer” technique to prevent digging underneath. This involves burying the mesh vertically into the ground for at least twelve inches. At the bottom of the vertical trench, the mesh should then be bent at a ninety-degree angle to extend outward horizontally for an additional twelve inches. This horizontal skirt acts as a persistent barrier that deters the animals when they attempt to dig near the fence line.
For protecting individual plants, bulbs, or seedlings, a similar material can be used to construct wire cages. These small enclosures should be placed over the plants and pushed slightly into the soil to resist burrowing attempts. Young fruit trees can be protected from girdling by wrapping the trunks with sheet metal cylinders. This prevents the squirrels from climbing the trunk to access the canopy or from damaging the base of the plant.
Deterrents and Garden Modifications
Modifying the garden environment makes the area less appealing to ground squirrels, forcing them to seek resources elsewhere. Eliminating readily available food sources, which are strong attractants, is a primary modification. This includes cleaning up fallen fruits, nuts, and berries from the ground and ensuring that bird feeders are either squirrel-proof or removed entirely.
Habitat modification involves removing potential nesting and hiding spots near the garden perimeter. Piles of brush, old lumber, or dense ground cover provide the rodents with secure shelter and easy access to burrowing sites. Clearing these debris piles makes the area more exposed, discouraging them from establishing residence close to cultivated plants.
Taste and scent repellents exploit the ground squirrel’s aversion to certain strong odors and flavors. Repellents containing capsaicin, the compound that gives chili peppers their heat, are effective because the spicy flavor is highly unpleasant to mammals. Similarly, strong scents like peppermint oil, garlic, or castor oil can be applied to the soil to deter digging and chewing. However, these treatments require consistent and frequent reapplication, especially after rain or irrigation, as their effectiveness diminishes quickly.
Active Removal Methods
When exclusion and habitat modification fail to control an established ground squirrel population, active removal methods may be necessary. Trapping is a practical solution for properties with low to moderate infestation levels. Live-catch traps are often discouraged because many local and state ordinances prohibit the relocation of captured wildlife due to disease concerns.
Lethal traps, such as box traps or Conibear-style body-gripping traps, provide a quick resolution and can be placed near active burrow entrances or travel pathways. For safety, lethal traps should be concealed or placed within a protective enclosure with a small, three-inch entrance hole to reduce the risk to non-target animals and pets. Baiting traps with favored foods like walnuts, oats, or melon rinds can increase their effectiveness.
Burrow fumigation is another method used to eradicate ground squirrels directly within their tunnel systems. This technique is most successful in the spring when the soil is moist, which helps to contain the gas within the burrow network. The most common fumigant available for residential use is the gas cartridge, which is ignited and placed inside the active burrow, then sealed to fill the tunnels. Before implementing any trapping or fumigation program, check with local agricultural commissioners or wildlife authorities regarding the legality and approved methods for ground squirrel control.