The eastern gray squirrel is not a California native, but you would not know it from the record. Its 9,516 sightings cluster hard in the urban Bay Area and the Central Valley: Santa Clara County alone holds 4,399, with San Francisco at 1,630 and San Mateo at 1,540, a distribution drawn by city parks and leafy suburbs rather than wild forest.
An easterner in California’s cities
Native to the hardwood forests east of the Rockies, the species was carried west and released in city parks in the early twentieth century, and it found California’s planted oaks, sycamores, and street trees entirely to its liking. It has since spread through Sacramento, where even the State Capitol grounds hold records, and along the coast through Golden Gate National Recreation Area and Henry Cowell Redwoods State Park. Where it thickens, it competes with the native western gray squirrel, which fades as neighborhoods replace oak woodland.
Two peaks on the calendar
Eastern grays breed twice a year, once in late winter and again in early summer, and the record shows it: counts spike in April, dip through the hot months, then surge again in September as the year’s second litters leave the nest and every squirrel in the park is burying acorns against winter. They never hibernate, so the count never falls away; this is a fixture of the urban landscape in every month.
Status in California
California does not specifically list the eastern gray squirrel under its state conservation framework, and the IUCN treats the species as Least Concern. In this state it is an established non-native, abundant in towns and cities rather than part of the wild fauna.
Full species profile
