Squirrels are common throughout San Mateo County, including urban and suburban areas. In the wild they nest in trees and feed on nuts, fruits, and buds. However, they may sometimes damage property by nesting in attics.
Squirrels will not usually create their own opening to a structure, but may enlarge an existing opening by gnawing. You can prevent this by ensuring that there are no gaps or holes that will allow a squirrel to enter your attic. You should also use a chimney cap to keep squirrels and other animals out of your chimney.
Squirrels may also become a nuisance when they become accustomed to being fed by humans. They can become bold and aggressive, and may bite or scratch people. You should avoid feeding squirrels, and use a squirrel-proof bird feeder if necessary. NEVER feed squirrels by hand, even if they seem tame.