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Metro naturalist James Davis tells you all about the "beautiful rodents" that are making a home in the oak woodlands of Cooper Mountain Nature Park.
By Metro naturalist James Davis
Cooper Mountain is home to what many would consider the most beautiful rodent in America. “What? A beautiful rodent?” you may ask, thinking of drab rats and mice. Yes, there are good looking rodents and the Western gray squirrel is one of the most handsome.
Chris Maser, in “Mammals of the Pacific Northwest,” says “When bounding over the ground, these squirrels are grace and flowing beauty in motion. Their long, plumy tails seem to float out behind them as they cover the ground in long, easy, rolling leaps, which cause people, including me, to stop and admire them.” How’s that for a glowing description of a rodent?
The Western gray squirrel, sometimes called the “silver gray squirrel,” is indeed gray but its fur is a bright, silvery gray with white tips that is as beautiful as gray fur can be. With their huge fluffy tail, overall big size and bright white undersides, “Western grays” are fairly noticeable for a rodent. Like all tree squirrels they are active during the day, making them easy to see.
Western gray squirrels used to be common in oak woodlands, pine forests and drier mixed forests with Douglas fir but today are classified as threatened in Washington and their range has decreased in Oregon. Because of the loss of oak woodlands in the northern Willamette Valley, the presence of Western gray squirrels on Cooper Mountain is significant because it indicates that the nature park retains enough oak woodland to provide habitat for the Western gray. Restoring and enhancing oak habitat is one of the primary management goals for Cooper Mountain.
Like other tree squirrels, Western grays use cavities in trees for shelter and nesting but also build “outdoor nests” in trees, called dreys, out of leaves and sticks. Most people have never heard the word drey (sometimes spelled “dray”) but they are easy to see in the winter in areas with lots of big, old, deciduous trees. If you look up into a bare tree in winter and see what looks like a big ball of leaves about the size of a soccer ball attached to some branches – that’s a drey.
As is typical for all tree squirrels, Western grays are easiest to see in the fall when they are the most active, busily storing nuts for the winter. Like the two introduced squirrels common in the region, the Eastern gray squirrel and the Eastern fox squirrel, our native Western gray “scatter hoards” or buries nuts one at a time over a large area. Our other native tree squirrel, the Douglas squirrel or chickaree, is a “larder hoarder,” stashing all the fir cones it has gathered into one or two hollow logs for the winter. Because the Douglas squirrel literally has all its nuts in one basket, it is very defensive of is larder and is the one that chatters and scolds you when you are in its forest territory. And yes, tree squirrels do remember where they bury many of their nuts; but not as well as the jays do.
Explore the trails, natural garden and visitor facilities and enjoy the views and rare habitats at the new Cooper Mountain Nature Park near Beaverton.