This species belongs to the subgenus Otospermophilus. Externally the species beecheyi differs from Citellus washingtoni, townsendii, and columbianus, all of which belong to the subgenus Citellus, in possessing more slender limbs, a longer, thinner body, a rather bushy tail that is nearly two-thirds, rather than less than half, the length of the body, and larger, more prominent ears. The Beechey ground squirrel lacks also the hazel color of nose and thigh that is characteristic of the subgenus Citellus in Washington.
Citellus beecheyi ranges from the southern edge of the state of Washington southward through western Oregon and California into northern Lower California. It is a western coastal species and reaches eastward only as far as Nevada. A related species, Citellus variegatus, occurs farther inland, from Utah, Colorado, and Texas, southward to central Mexico. Eight subspecies of Citellus beecheyi are recognized by [Howell] (1938), all but three of which are restricted to California.
At present the Beechey ground squirrel occupies a limited area of Washington, which it has invaded in recent years ([Scheffer] and [Dalquest], 1939: 44). However, it is extending its range and may be expected eventually to occupy a considerable part of the state.
The habitat of this ground squirrel is varied. It occupies a more humid terrain than do most members of the genus. At the present time it is most common in grassy fields and rocky outcrops along the Columbia River. It is common also in the open oak groves on the hillsides back from the river valley and some individuals were seen near Guler, well up on the slopes of Mount Adams. As observed in Washington, its favored habitat is about rock outcrops and talus slides near extensive fields or grasslands. In California and Oregon, however, it occurs among other places, in scattered fields and meadows of the coniferous forests in the humid subdivision of the Transition Life-zone. The range of tolerance of the species is such that it might extend its range into much of western Washington, including the Puget Sound area. It may be expected to move northward through the eastern Cascades.
Because of its limited range and the short time of its establishment, the Beechey ground squirrel has been studied little in Washington. According to [Howell] (1938: 28), this race is less prolific and abundant than other members of the species. Of the Beechey ground squirrel, certainly the subspecies C. b. douglasii, is less common, locally and over wide areas, in its range in California and Oregon, than are the subspecies C. b. beecheyi and C. b. fisheri in California. In Washington, on the other hand, douglasii is locally abundant, perhaps more so than elsewhere.
The habits of this race in California have been studied by [Grinnell] and Dixon (1919: 595-807). Burrows have been excavated near Eugene, Oregon, and the findings published ([Edge], 1934: 189-193). Burrows were dug on sloping or well-drained ground. Mounds of earth at the entrances were usually inconspicuous but well-worn trails led to the burrows. The burrows entered the ground at an angle of 35° for about two feet, then flattened out horizontally for six feet or more. The burrows were from 1 to 4 feet deep, usually about 2 feet. Ordinary burrows had a single entrance but some older burrows had two or more. Burrows branched frequently. Nest chambers were of the shape of a flattened sphere 10 inches in diameter. Frequently more than one nest was found in a burrow, but only one was in use at a time. Some nests were infested with fleas. Nests frequently contained food. Most of the burrows observed by me had their entrances beside rocks or oak roots. In alfalfa fields near Bingen and Lyle, Klickitat County, the burrows were in open fields and the entrances were marked by large mounds of earth. In actual diameter the burrows seemed smaller than those of Citellus columbianus.
Aestivation and hibernation of the ground squirrels in the lower Columbia River Valley seem unnecessary, for the climate is temperate and humid. It is not established that douglasii hibernates in other parts of its range where the climate is mild. Specimens shot at White Salmon in early March were lean and gave no evidence of having hibernated.
The Beechey ground squirrel is an excellent climber; I have seen individuals in oak trees on a number of occasions. They like to sit on fence posts and when alarmed descend head foremost, with speed and agility. In running on the ground their movements are more graceful than those of Citellus columbianus but are unlike the flowing, bounding run of tree squirrels.
Near White Salmon and Lyle, these ground squirrels were eating burr clover (Medicago), grasses (Bromus), and alfalfa. In some places they do considerable damage to alfalfa fields. They probably eat acorns and are said to eat some insects.
In California the young are born in May and number five to seven.