ALLEN CHIPMUNK. Eutamias senex (Allen)

Field characters.—Size large for a chipmunk (head and body about 5-1/2 inches long, tall about 4-1/4 inches). (See table in footnote 15, page 177, for detailed measurements.) Usual chipmunk pattern, markings indistinct; general tone of coloration dark grayish. (See pl. 3g). Distinguished from frater by larger size, duller coloration, and less conspicuous light striping on sides of head and back; from quadrimaculatus by more grayish coloration, shorter ears, and less conspicuous light spots behind bases of ears; from alpinus by much larger size and by duller and darker coloration. Voice: Similar to that of the Long-eared Chipmunk.

Occurrence.—Common resident in Canadian Zone on west slope of Sierra Nevada. Recorded from Aspen Valley, Cascade Creek (near Gentrys) and Chinquapin eastward to Glen Aulin and Washburn Lake, at altitudes of 6200 to 7700 feet regularly, and exceptionally at 4600 feet (Lady Franklin Rock) and 8100 feet (Porcupine Flat). Lives in thickets and about logs, rarely going over 5 feet above the ground.

The Allen Chipmunk is the common brush and log inhabiting species in the belt of country on the west slope of the Sierra Nevada characterized by the presence of huckleberry oak, chinquapin, and snow bush (C. cordulatus). By reason of its large size (pl. 3g), gray coloration, and terrestrial proclivities it may be told at a glance from the smaller, more brightly-marked tree-climbing Tahoe Chipmunk sharing the same belt.

Along the lower margin of the Canadian Zone the Allen and Long-eared chipmunks are found together. The former exhibits a grayer-toned pelage, with more obscured striping, shorter ears, and a much less conspicuous whitish spot behind the base of each ear. The habits of the two, so far as we know them at present, are alike, save perhaps that the species now under discussion is the more closely confined to the ground, low brush, and prostrate logs. At the upper edge of the Canadian Zone the Allen Chipmunk in a few places meets the small, pale-colored, rock-dwelling Alpine Chipmunk, from which it differs so greatly as to be easily distinguished. At no station visited by our party were the Allen and Mariposa chipmunks found near each other. An interval of a thousand feet or more of altitude ordinarily separates the ranges of these two species, which are of similar size and much alike in general markings. They may thus be identified most conveniently, perhaps, on the basis of the altitude of their occurrence.

One rather notable departure in range for the Allen Chipmunk was shown by the capture of an individual at Lady Franklin Rock (altitude 4600 feet) in the gorge of the Merced just below Vernal Falls. We rather expected to find the Long-eared Chipmunk there, but instead the one animal taken turned out to be an Allen Chipmunk. The spot named is an attractive picnic place for leisurely inclined tourists from the Valley and a way station for hikers en route to or from Glacier Point or the Little Yosemite, and the chipmunks (for there are usually two or more about) profit by the crumbs and scraps of lunch dropped there or intentionally thrown out to attract the animals to close view.

The few facts at hand regarding the breeding season of this species indicate that it begins in May or perhaps even earlier. A female captured near Tamarack Flat, May 26, 1919, contained 4 embryos, another captured near the upper Yosemite Creek on June 4, 1915, contained 5 embryos, and one taken near Porcupine Flat, June 27, 1915, contained 2 embryos. Several individuals obtained in Indian Cañon between June 20 and 25, 1915, gave indication of having recently suckled young. The young probably appear abroad in early July. A young-of-the-year taken near Merced Lake on August 25, 1915, was already over three-fourths grown.

In the Canadian Zone woods one may find many of the vantage places to which these chipmunks have repaired when shucking out seeds. One such place was seen near Tamarack Flat. It was on the top of a mass of granite which stood up in rather solitary fashion overlooking much brushy territory. A chipmunk had been seen at the place and upon our climbing to the spot we found some shells from seeds and scales from pine cones. There is never so large an accumulation as that which constitutes the 'kitchen middens' of a Red Squirrel, probably because in many instances the chipmunk is apt to carry seeds about in its cheek pouches and shuck them out here or there wherever opportunity offers, instead of resorting to one fixed shelling station.

Contents of cheek pouches in four of these chipmunks gave analyses as follows: (1) Aspen Valley, October 19, 5 seeds of sugar pine; (2) near Glen Aulin, October 1, 15 seeds of Jeffrey pine; (3) Washburn Lake, August 28, 45 shelled grass seeds, probably of wild brome; (4) Merced Lake, August 20, 42 grains of barley (rolled), picked up where horses had been fed.