Facts About Washington Squirrels

Food and Feeding Habits

• Tree squirrels feed mostly on plant material, including seeds, nuts, acorns, tree buds, berries, leaves, and twigs. However, they are opportunists and also eat fungi, insects, and occasionally birds’ eggs and nestlings.
• Squirrels store food and recover it as needed. Hollow trees, stumps, and abandoned animal burrows are used as storage sites; flowerpots, exhaust pipes, and abandoned cars are also used.
• Scientists credit flying squirrels with helping forest health by spreading species of fungi that help trees grow.

Nest Sites

• Tree squirrels construct nursery nests in hollow trees, abandoned woodpecker cavities, and similar hollows. Where these are unavailable, they will build spherical or cup-shaped nests in trees, attics, and nest boxes.
• An alternate nest may be constructed in a tree for summer use. In areas with prolonged periods of cold weather, red squirrels may construct a winter nest underground, often in or near a food storage site.
• In urban areas, squirrels mostly nest in buildings and other structures.
• Nests contain leaves, twigs, shredded bark, mosses, insulation, and other soft material.

Reproduction

• Depending on the species, tree squirrels mate from early winter to late spring. One litter of two to four young is produced from March to June.
• All except flying and western gray squirrels may produce second litters in August or September.
• At about 30 days of age, the young are fully furred and make short trips out of the nest. At about 60 days of age, they begin eating solid foods and venture to the ground.
• At about three months of age, juvenile squirrels are on their own, sometimes remaining close to the nest until their parent’s next breeding period.
• The second litter may stay with the mother in the nest through the winter until well after the winter courtship season.

Mortality and Longevity

• In trees, squirrels are relatively safe, except for an occasional owl or goshawk.
• On the ground, large hawks and owls, domestic cats and dogs, coyotes, and bobcats catch squirrels.
• Vehicles, disease, and starvation also kill squirrels.
• Most squirrels die during their first year; if they survive that, they live three to five years.

This information was provided by the Washington State Department of Fish and Wildlife, Russell Link, and Michael Holmquist

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