CHIPMUNKS 185 



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. 



Mariposa Chipmunk. Eutamias merriami mariposae Grinnell and Storer 



Field characters. — Large for a chipmunk (pi. 3/) ; length of head and body about 

 5^/4 inches, tail 4% to 4% inches (see table in footnote 15, p. 177, for detailed measure- 

 ments). Dullest colored of all the Yosemite section chipmunks; light stripes indistinct, 

 not white; spot behind ear grayish; general tone of coloration dull reddish brown in 

 summer coat and grayish brown in winter. Voice: A hollow-sounding iock, repeated at 

 regular intervals; when excited, a high-pitched whislc, repeated; also a rapid sputter 

 of four or more syllables. 



Occtirrence. — Eesident in small to moderate numbers in Upper Sonoran and low 

 Transition Zones, on west slope of Sierra Nevada. Recorded from Mast (700 feet 

 altitude near Pleasant Yalley), eastward to Columbia Point (altitude 5000 feet) on 

 north wall of Yosemite Valley. Inhabits brush and trees, especially oaks, rarely ascend- 

 ing latter to 25 feet or so above the ground. 



The Mariposa Chipmunk is the local representative of a group (the 

 Merriam Chipmunks) which is found commonly at middle altitudes in the 

 mountainous portions of southern California. This is the only chipmunk 

 known to occur on the floor of Yosemite Valley, and there, as well as at 

 other stations within its local range, it is remarkably scarce as compared 

 with the number of chipmunks higher in the Yosemite section. 



The westernmost station of record for the Mariposa Chipmunk is Mast, 

 in the lower Merced Caiion. Upon none of our visits to Pleasant Valley, 

 only a little lower down, did we get any trace whatsoever of chipmunks. 

 The animals were moderately common in the mixed stands of trees and 

 brush near the old Merced Gold Mine mill west of Coulterville, and a 

 number were recorded at El Portal. In Yosemite Valley, as at Kocky 

 Point and similar places along the sides of the Valley floor, the rough talus 

 slopes grown over with manzanita and golden oaks were found to be the 

 best locations in which to seek the animals. No Mariposa Chipmunk 

 was seen higher than Columbia Point, altitude 5000 feet, on the Yosemite 

 Falls trail. 



Compared with other chipmunks of the region this species is the largest 

 and the least strikingly colored. (See pi. 3/.) There is a prevailing 

 dullness to the pelage, especially to the gray winter coat, even more notice- 

 able than in the Allen Chipmunk. We did not actually see Mariposa 

 Chipmunks at any locality where any of the other species occurred. It 

 seems not unlikely, however, that the range of the Mariposa will be found 



