While some may find them cute, both the Eastern gray squirrel (Sciurus carolinensis) and the Eastern fox squirrel (S. nigeri) are actually invasive species in California. They are two of four species of tree squirrels found throughout the state. Regulations regarding management of tree squirrels is complicated, so it is important to be able to identify squirrels to species level.
Eastern gray squirrel. (Credit: JP Clark)
The Eastern gray squirrel is established in San Francisco, Calaveras, and San Joaquin counties and may be expanding their range. They are mostly gray in color, as their name suggests, and have relatively narrow tails and short ears. Management requires a permit from the California Department of Fish and Wildlife if land or property is being damaged.
Eastern fox squirrel. (Credit: CL Christie)
The Eastern fox squirrel is established in most major cities in California and can be identified by their grizzled yellow-brown coat, tan to reddish-brown underside, and bright orange-brown ears. It is considered the most serious pest of homes and gardens in urban and suburban environments. The eastern fox squirrel is the only tree squirrel that can be managed without a hunting license or permit as long as management is in line with the California Fish and Wildlife Code and Regulations.
For more information about these and other squirrel species, you can read our two part blog post here and here. Our Pest Note: Tree Squirrels also has more information on the biology and behavior of tree squirrels as well as additional management information.