SAGEBRUSH CHIPMUNK. Eutamias pictus (Allen)

Field characters.—Size small (head and body 4 inches tail about 3 inches long). (For comparative measurements see footnote 15, p. 177.) Usual chipmunk pattern of markings; general tone of coloration pale, grayish. (See pl. 3e). Stripes on back dark brown and white, more highly contrasted than in Alpine Chipmunk; size somewhat smaller, tail shorter, and sides of body less deeply brownish than in Mono Chipmunk. Voice: A high-pitched tsew; also a rapid series of chip-ing notes.

Occurrence.—Abundant in Transition Zone east of Sierra Nevada, from Williams Butte eastward all around Mono Lake. Altitude ranging from 6400 to 8000 feet. Restricted to sagebrush association where it runs on ground or climbs up into the bushes.

The Sagebrush Chipmunk is to be looked for in the extensive tracts of sagebrush which cover the floor of the elevated inland desert surrounding Mono Lake. The prevailing gray tone of the region has been impressed on the chipmunk's pelage, though not to the degree shown in certain birds of the region. (See pl. 3a). Yet the alternating stripes of dark brown and ashy white on the back are well contrasted. The species name pictus, meaning painted, seems highly appropriate, for the coloring looks as if it had been applied by lengthwise strokes of a brush.

No one need have special difficulty in identifying the Sagebrush Chipmunk in the Yosemite region, for it here keeps almost entirely to the one sort of shelter, namely, pure growths of the sagebrush, and it is the only species of chipmunk ordinarily found there. Along the line of contact where the sagebrush and mountain mahogany meet, the Sagebrush and Mono chipmunks may at times occur together. There is no certain way of distinguishing these two out of hand. A larger, heavier, and more brownish colored animal which keeps to the heavier chaparral and vicinity of trees is likely to be monoensis, while a smallish gray-toned individual which runs on the ground beneath the bushes is probably pictus.

In size and general habits the Sagebrush Chipmunk is most like the Alpine Chipmunk. It is an active animal, running about on the ground a great deal, and carrying its tail up in a prominent manner, nearly or quite perpendicular to the back, as it goes. Sometimes several of these animals will play about a brush patch, as many as six having been noted together on one occasion. Now and then one individual will give chase to another and a long continued pursuit will follow. Although giving voice to the usual calls of chipmunks when occasion demands, this species is, as a rule, rather quiet. When frightened, an individual will take shelter beneath or within the densest brush.

The Sagebrush Chipmunks were still active when our party quitted the Mono country on September 23, 1915. In the spring of 1916, the first definite record for the species was made on May 18, although the animals must have emerged from hibernation at a much earlier date. A female captured on this date was already suckling young. In favorable areas there is a large population of these animals. More than two dozen were noted in one hour on the morning of September 17, 1915, while one of our party was going from Williams Butte toward Mono Craters. On several other occasions during the same week six an hour was the average seen.

Some Sagebrush Chipmunks captured near Williams Butte on September 23, 1915, had their cheek pouches crammed with seeds of Kunzia, which, to the human taste, are exceedingly bitter.