The Western Gray Squirrel is the largest native tree squirrel in the western United States. They are generally between 14-35 ounces and 18-24 inches in length. The fur on their back is silver gunmetal in color with white underneath and sometimes flecks of black in their tail. In winter, the backs of their ears may turn a reddish-brown. Their tails are long and bushy, but young squirrel tails will not reach full fluffiness until adulthood. When frightened, squirrels will spread their tails using them as camouflage from overhead predators.
Squirrels will molt from head-to-tail in the spring, but only from rump to head (excluding the tails) in fall. Squirrel moms may use their tail fur to line their nests before giving birth to young.
They eat a wide variety of foods; berries, nuts, pine seeds, acorns, green vegetation, some insects and eggs of small birds. They will find acorns caches by scent. They also like the tomatoes in your garden, generally only one bite in each tomato! So keep it fenced with chicken wire to keep them out.
Squirrel nests are called dreys. Built in the top third of trees and made of sticks and leaves held together with long pieces of grass. They make two types of nests; one for winter and birthing and raising young and a second used as a sleeping platform. Young squirrels may also sleep spread-eagled on a high tree limb in hot weather.
Squirrels mate from December through June having one to two litters per year. Litters vary from 1 to 5 kits. Juveniles leave the nest between March and mid-August.
Wild western gray squirrels have lived up to 10 years. But they are prey for bobcats, hawks, owls, eagles, mountain lions, coyotes, domestic cats, raccoons and humans. Squirrels depend on auditory alerts from other squirrels and birds. Once they hear an alarm call, other squirrels will join in with the chirping so everyone is aware of danger.
Western gray squirrels are threatened with habitat loss, road-kill mortality and disease. Our recent devastating fires have removed much of their habitat. The eastern fox squirrel and eastern gray squirrel, introduced species, are more tolerant of humans who may provide food. Our native western gray squirrel population in California is stable, but these introduced species are having a negative impact.
Squirrels are scatter-hoarders storing several caches of readily available food. Their digging in the soil aerates the soil making the acorns they miss repopulate our oak forests. Some animal experts consider squirrels as nature’s gardeners since the scattered seeds ensure the survival of many plants and trees.