Look-Alike Pests and Damage
Before beginning any management plan, it is important to correctly identify the species of squirrel responsible for damage and to be aware of any legal restrictions.
Other Squirrel Species
It is not difficult to distinguish tree squirrels from ground squirrels. As their name implies, a startled tree squirrel will generally run up a tree, while a ground squirrel will typically retreat to an underground burrow. Ground squirrels may climb to lower tree limbs and to the top of fence posts, but they are rarely seen very high in trees, and tree squirrels almost never retreat into burrows in the ground.
Non-pest ground squirrels
Several species of ground squirrel may occur in your area, and not all of them are considered pests. Learn about these non-pest species and their ranges here.
There are many burrowing rodents in California. Some of these are considered pests, but other wildlife may also use abandoned ground squirrel burrows. It is important to determine whether or not a burrow is being actively used by a ground squirrel to avoid harming non-target species.
Rats (Rattus spp.)
Rat burrows are generally slightly smaller in size compared to California ground squirrel burrows. Roof rats (Rattus rattus) typically nest above ground, but in fruit and nut orchards, they may make burrows at the base of trees. Although Norway rats (Rattus norvegicus) burrow underground, they are less frequently considered agricultural pests. It is important to distinguish which rodent species is present before a control program is undertaken.
Pocket Gophers (Thomomys spp.)
Pocket gopher burrows are closed systems, and burrow openings are generally plugged unless the gopher is in the process of pushing excavated soil to the surface. Feeding holes may be open on occasion, but these are usually about 2 inches in diameter, smaller than California ground squirrel burrow openings. Pocket gopher mounds are usually crescent shaped with a circular plug evident where the burrow entrance has been closed.
Voles (Microtus spp.)
Vole burrow entrances are much smaller than California ground squirrel burrows (1.5-2 inches) and are generally found in dense vegetation. Runways can be seen aboveground connecting the burrows.
Moles (Scapanus spp.)
Mole burrows are usually closed systems, and their underground tunnels are not generally evident. However, they may make feeding tunnels just below the soil surface, which appear as raised cracked ridges. Their mounds are conical and usually quite symmetrical.