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Friday, January 29, 2010

Squirrels in Portland

Since I've been back in Portland I've been pondering what's going on with local squirrel populations. As long as I can remember, I've noticed two main squirrel species in the area: the introduced eastern fox squirrel (by far the most common) and the smaller, native Douglas squirrel. Both are reddish-brown squirrels.

Eastern fox squirrel

In recent months, I've also noticed an increased number of gray squirrels in the Portland area. This of course gets the naturalist in me wondering, and I've been trying to figure out what type of squirrels these are and where they've come from.

There are two main possibilities: the eastern gray squirrel and the western gray squirrel. The western gray squirrel is native to the region but is described as having dramatically reduced populations in the region. The eastern gray squirrel has been introduced to the west, and the Audubon Society states that they have been established in Vancouver, WA for over a decade and have recently been expanding into the Portland area. After looking at images of both species in field guides and online I have to say they look pretty similar, though the eastern gray squirrel is described as being significantly smaller than the western gray squirrel.

Eastern (?) gray squirrel

My tentative conclusion is that I've been seeing eastern gray squirrels. My main reasons for this are the fact that they don't seem very skittish, as the western gray squirrel is described, and the amount of red the permeates their otherwise silvery-gray fur. I'm going to continue looking into the squirrel species distributions in Portland, but if anyone has any insight or knowledge about differentiating between eastern/western gray squirrels, your thoughts would be much appreciated!


Warren Baker said...

They greys have usurped our Red squirrels over here Monika. They carry a deadly plague that the reds have no immunity to. :-(

Wally said...


Western Gray squirrels are substantially bigger than Eastern's and their hairs are more obviously "tipped in gray". Your photo looks like an Eastern Gray. Interestingly, my students and I at Mt. Hood Community College are undertaking some research on these squirrels and I'd like to talk with you about getting location data on the squirrels you are finding.


Wally Shriner

Anonymous said...

Eastern Grays are pretty common down in Salem. I think they are the dominant squirrel at the Capitol, Willamette University, and Bush Park. Up in Beaverton (where I live now), the Eastern Fox squirrel is most common. We had lots of Western Grays in So. OR when I was growing up in the 1980s. I think they are still pretty numerous there.

Jim Boone said...

Thanks for your post. Your gray squirrel is an Eastern Gray. You can remove the question mark in the photo caption. Western Grays are larger, have a much bushier tail, and generally are creatures of the oak forest rather than conifer forests.