The most common squirrel to cause trouble, the Eastern Gray is an invasive species that has found its way to our state from the east coast. They are bigger, stronger, and more aggressive than our native Douglas squirrels, and have been winning in the competition for suitable habitation. Able to thrive in an urban enviroment, they commonly get into the homes of the people that feed them, or their neighbors.
One of Washingtons native squirrel species, these little guys love to talk! You can commonly hear their chirps and chitters if you live in the eastern, more wooded part of the Puget Sound area, from Woodinville to North Bend. They can be deceptive, and are small enough to squeeze into very tiny openings, sometimes not leaving any trace that they have entered into a home at all.
Although a much rarer occurrence than its land-locked brethren, our native flying squirrels do find themselves in attics from time to time. They are another protected species, with smaller numbers than the Douglas squirrels. Issaquah/Newcastle and Black Diamond are the only "common" areas I've come across them, with random pockets in other locations