The largest native tree squirrel in the West, named from a historic expedition
The western gray squirrel was first described by naturalist George Ord in 1818, based on notes taken by the Lewis and Clark expedition near The Dalles in Oregon. It’s the largest tree squirrel native to the western United States, with a silver-gray coat and a notably long, bushy tail. Unlike the eastern gray squirrels that thrive around people, this species depends on large, connected stands of oak, pine, and other conifers, and it doesn’t adapt well to fragmented or urban habitat.
A mast-eating forager, with the occasional surprise
Recorded food sources for this species include acorns from coast live oak and valley oak, California buckeye, walnuts, gray pine seeds, and bigleaf maple, a classic mast-based diet built around what western oak and conifer forests produce each fall. A recorded instance of it feeding on a dark-eyed junco is a reminder that tree squirrels will opportunistically take eggs, nestlings, or other easy protein when the chance arises, even though seeds and nuts make up the bulk of its diet.
A western range, active almost entirely by day
Records for the western gray squirrel run heaviest in California, with smaller but steady numbers in Oregon, Nevada, and Washington. Activity data shows it’s almost entirely diurnal, active through the day and quiet at night, and reports hold fairly steady across the year rather than showing one sharp seasonal peak. Elevation records run from sea level up to nearly 8,900 feet, though the median sits below 1,600 feet, showing most sightings happen in lower forested country.
Predators and mounting pressures
Bobcats, coyotes, bald eagles, and red-tailed hawks all appear as documented predators of the western gray squirrel. Beyond direct predation, the species faces recorded pressure from habitat fragmentation, roadkill mortality, and disease, three factors that likely explain why populations have declined in parts of its range even though the IUCN still lists it as Least Concern.
