Page:Natural History of the Ground Squirrels of California.djvu/77

Rh beginning hibernation at the same points was one and one-half to two weeks later. Individuals have been reported to us as seen aboveground as late as the first week of September, but all reports agree that the majority are "holed up" before the first week in August.

In the spring the animals reappear often when there is yet much snow on the ground. In 1916 they were out in force on March 16, when they had burrowed up in places through two feet of snow and were nibbling the sagebrush tips (W. C. Jacobsen, MS).

Enemies of the Oregon Ground Squirrel were, under original conditions, doubtless numerous and effective in keeping down its numbers. Gopher snakes, rattlesnakes, badgers, coyotes and Swainson Hawks are known to feed regularly on it. Mr. J. O. Miller, a professional trapper living at Yreka, informs us that nine out of ten coyotes trapped by him during the summer months have remains of ground squirrels in their stomachs. One coyote taken in Butte Valley had parts of seven Oregon Ground Squirrels in its stomach. An old-time resident near Alturas told the senior author that the killing off of the "varmints" (predaceous animals) in recent years seemed to him to have had something to do with the increase and spread of ground squirrels. We are strongly inclined to his belief. Encouragement of those natural enemies which are not in themselves seriously detrimental to man's interests would go far to check the undue increase of the ground squirrels.

Other names.—Belding Spermophile; Bob-tailed Spermophile; Prairie Dog, part; Picket-pin, part; Spermophilus elegans; Spermophilus beldingi; Colobotis beldingi.

Field characters.—A medium-sized, short-tailed, "picket-pin" type of ground squirrel, without side-stripes or other conspicuous markings, but with bright reddish brown back. Length of body alone about $7 4/5$ inches, with tail $2 2/3$ inches more. (Closely similar to Oregon Ground Squirrel, but smaller and with back reddish brown instead of brownish gray; compare figs. 20a and 20b.)

Description.—Adult in full fall pelage: Sides of head, hind neck, shoulders, sides of body and flanks continuously yellowish brown (numerous fine hairs which are chiefly black, though light-tipped, lend a dusky tone to these areas); a tinge of olive-ochre pervades the lower margins of those areas adjoining the light underparts; eyelids white; whiskers black; ears dusky, finely haired, not tufted; crown of head to nose, tawny-olive; a broad sharply outlined band of bright hazel brown running down middle of back from between shoulders, narrowing to base of tail. Tail short, full-haired, flatfish; above mixed hazel and black, black predominating toward end, where also a well-defined buffy white fringe; under surface of tail conspicuously deep cinnamon-rufous, with subterminal black interval, and buffy white fringe all around. Upper sides of feet buffy white; claws chiefly black, with horn-colored tips; palms naked; soles naked save for sparse hairing from heel halfway to tubercles. Under side of head and neck, and inner sides of fore and hind legs, buffy white; belly cream-color, with lead-color of bases of hairs showing through.

Color variations.—As far as we can see from the series of specimens studied, adults molt but once a year, during July. May and June specimens show clearly the effects of wear and fading, and are grayer, with the mid-dorsal brown area much duller than in the fresh pelage described above. Young not one-fourth grown are like adults in color, but with mid-dorsal area paler, snuff brown, and under side of tail clay color.