Western gray squirrel (Sciurus griseus)
Even though Squirrel Appreciation Day is over for 2023, we can still take some time to appreciate a beautiful, beneficial, local squirrel. Meet the western gray squirrel (Sciurus griseus).
As their name implies, western grays live only on the West Coast. Their range runs from Lake Chelan and Tacoma, Wash., southward through central and western Oregon, west-central Nevada, and the coast ranges and Sierra Nevada of California to the montane areas of southern California and extreme northern Baja California.
With a 12-inch body and another 12 inches of tail, the western gray is the largest native tree squirrel in our area. Not only are their tails long, but they are also full and fluffy. Those fabulous tails help them balance as they nimbly jump from branch to branch, tree to tree high up in the canopy.
Western grays really put the “tree” in “tree squirrel.” While they do sometimes come down to earth to store food, they spend most of their time running around their branchy squirrel highway. They prefer to jump no more than three feet from branch to branch, and who can blame them when they’re often jumping around 75 feet up in the air?
If you’re lucky enough to have gray squirrels in your yard, you can observe them taking the same route through the treetops day in and day out.
A leafy superhighway is one of the western grays’ special habitat needs. They need a high canopy with lots of connected branches, and they prefer that at least some of the branches belong to oak trees.
Oak trees are the western grays’ favorite nesting trees. They’ll build their nests in hollows which offer both adult and baby squirrels warmth and protection. They make those nests cozy by packing in a variety of mosses, leaves and even ponderosa pine needles.
Grays don’t hibernate in winter but will hole up in their nests during the worst weather days. Nice days are spent gathering food for the icky days. Western eat seeds, nuts, acorns, tree buds, berries, leaves and twigs. They are opportunists and will eat fungi and insects.
They’ll also disperse fungi and seeds, and that’s quite beneficial for our forests. They disperse hypogeous fungi (soil fungi that produce macroscopic fruit-bodies partially or completely embedded in soil or humus). The fungi facilitate nutrient and water uptake in pine, oak and Douglas fir roots.
As for seed spreading, grays bury a lot of seeds for future meals. Grays go back for many of these seeds using a combination of their excellent memory and seed-seeking sense of smell. However, they don’t retrieve all the seeds, and many of their leftovers germinate and keep woodlands thriving.
Western grays as a species are not thriving. They’ve been in decline since at least the early 90s. They are listed as a sensitive species in Oregon and as a threatened species in Washington.
In our area vehicles and wildfire are their biggest threat. In other areas of Oregon habitat loss and competition from the bolder, larger (body length 16 – 20”) non-native eastern gray squirrel (Sciurus carolinensis) pose problems for the western gray.
Like other squirrels, western grays have an alarm bark, so you might hear them before you see them. If you’re getting “barked” at while out and about under the canopy, look up and you might spot the clean white belly of one of our helpful, silvery squirrels.