Closely associated with oaks. Require large trees, mast, and snags. Home ranges of males overlapped considerably. Breed from January through September, with most births occurring March into June. Potential predators include coyotes, foxes, bobcats, martens, and large hawks and owls.
Heavy snowfall covers stores of buried food, and increases predation pressure.
May damage commercial fruit and nut crops. Local populations occasionally decimated by disease. Numbers have been reduced by removal of snags, duff, slash, or oak trees. Western gray squirrel study in Kern County, California. Fish and Game, Wildl.