Ranging throughout the western third of Oregon, California Ground Squirrels (Spermophilus beecheyi) are much larger and bushier-tailed than other ground squirrels. They are found in open grasslands (including large lawns) and on rocky outcrops. Unlike other ground squirrels, they will also climb trees to obtain food. A colloquial name for this species is Gray Digger.
This female with her two young had a burrow at the base of a large tree at the Portland Rose Garden. Notice that when the fur is ruffed up, as on this individual, the white spots are much harder to see, making it harder to differentiate this species from one of the tree squirrels. California Grounds Squirrels can be solitary or live in loose colonies. When living in a colony, each individual has their own private burrow entrance.