The most common tree squirrel in Western Washington is the non-native Eastern Gray Squirrel. Introduced into the Seattle area in the early 1900s, it has become well established in cities and suburbs.

Gray squirrels are active during the day, especially early morning and late afternoon. Gray squirrels build large nests of leaves and twigs on tree branches or within tree cavities. They also nest in buildings where they can gain access through open spaces in the roof, attic or walls.

Although they do not hibernate, squirrels often remain in their nests in cold or stormy weather, venturing out when they need to find food, which they often have cached near their nests.

Eastern Gray Squirrels are omnivorous. They eat seeds, nuts, tree bark and buds, fungi and occasionally eggs and nestling birds. Like other rodents, squirrels are gnawers, using their sharp, constantly growing front teeth to strip bark and chew through wood and plastic.

Breeding season begins in late winter. Depending on conditions and food availability, squirrels may produce two litters a year. Average litter size is three, and the babies are born naked and blind. Young squirrels remain in the nest for about six weeks.

Solving and preventing conflicts

Squirrels are opportunistic, making use of all sources of food and shelter available to them. They can also cause property damage, gnawing through electrical wiring or overturning bird feeders. The best way to discourage squirrels is to change your property to make it unappealing to them.

Do not feed squirrels

  • Discourage squirrels from raiding bird feeders by placing them at least six feet away from fences, trees, and buildings or by hanging them under steeply domed baffles.
  • Do not put bread, popcorn or other leftovers out for them. Even if you enjoy feeding squirrels, your neighbors may end up having problems with the animals, and often, people turn to harmful, inhumane means for solving these problems.

If squirrels have moved in

Squirrels, especially adult females, seek openings for potential den sites, and a house in poor repair is an invitation to move in. Gnawing to enlarge holes, squirrels can enter through small spaces. If you suspect a squirrel is living in a wall or attic, look for likely entries and listen for telltale scampering sounds.

  • Assume there are babies in the nest from March through September. You need to wait to seal the nest until they are old enough to leave on their own. When you are positive the juveniles are gone, you can begin closing the squirrels out of the space.
  • Frighten them away with a radio set to a talk station or other loud noises, or wait until they have gone outside during the day.
  • If you aren't sure that all the animals have left, you can leave one hole open and fit it with a one-way door that has a hinged flap so the squirrels can leave but not re-enter. Leave the door in place for several days, listen for activity, and if possible inspect the space regularly until you are certain the squirrels are gone.
  • Once you are sure all animals are out, seal the openings with half-inch hardware cloth or metal flashing. Be sure to extend the seal over the hole at least six inches in all directions to prevent squirrels from gnawing through it.
  • If a squirrel is running freely in your living, a bedroom or office, first close surrounding interior doors. Keep windows or an exterior door open and leave the room while the squirrel finds his way out.

Prevent them from moving in again

Squirrels will return to a building with loose, holey or rotting siding, boards and shingles. Repair or replacement it is essential to squirrel-proof the building permanently. Also, trim branches away from the sides and roofs of buildings to prevent easy access.

Protect your garden

To keep squirrels from stripping bark or otherwise damaging trees, wrap a 24-inch metal cylinder around the trunk at least six feet high, and trim lower branches. Occasionally, squirrels dig up bulbs, which can be protected by laying chicken wire over the soil.

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