186 ANIMAL LIFE IN THE YOSEMITE 



to touch that of the Long-eared Chipmunk in certain places. The Mariposa 

 Chipmunk is much duller colored (decidedly less brightly broAvnish), as 

 compared with the Long-eared, and the spot at the hinder base of each 

 ear is only imperfectly indicated — dull gray instead of pure white; the 

 ear itself is decidedly smaller, not so tall. 



It seems likely that those Mariposa Chipmunks which live in the Upper 

 Sonoran Zone do not actually hibernate at any season of the year. They 

 probably remain in their retreats during rainstorms and come out on warm 

 days at any time during the winter months. But those individuals which 

 live in Yosemite Valley and elsewhere in the territory where snow remains 

 for some time during the winter months (Transition Zone), do, in all 

 probability, hibernate. Thus at El Portal, in the fall and early winter 

 of 1914, Mariposa Chipmunks were out and active until December 7, 

 perhaps later. The latest seasonal record on the wall of Yosemite Valley 

 is for November 19 (1915). None was seen anywhere in the Valley during 

 our intensive work there in December, 1914; nor was anything noted of 

 the animals during a visit to the Valley at the end of February, 1916. 



On the whole, the Mariposa Chipmunk seems to be a reclusive species. 

 It adheres to a dense type of vegetational cover, where also the range of 

 the observer's view is short. We found that occasional individuals would 

 chip noisily when one of us 'squeaked' at them, but more often the chip- 

 munks became silent after the first bit of noise or movement on our part. 

 At Blacks Creek one of several of these chipmunks to which we 'squeaked' 

 came within close range. The animal sat partly hidden from view in a 

 thicket and called hock, hock, hock, in long series about as fast as a person 

 could pronounce the syllables easily. Usually each note was accompanied 

 by a sidewise wave of the tail. When frightened by a movement on the 

 part of the observer, the chipmunk gave a rapid series of sibilant notes 

 and dashed off along branches toward some refuge, after which it remained 

 silent and gave no clue to its new location. 



The Mariposa Chipmunk, like others of its kind, is given to burying 

 food supplies in small pockets in the ground. Under some manzanita brush 

 on a hill west of the McCarthy ranch and about 3 miles east of Coulterville, 

 we found these caches common, though the animals themselves were notably 

 successful in keeping out of sight. 



The favorite haunts of this species in the foothill country seem to be 

 the mixed growths of brush and small trees. Seldom did we find them in 

 continuous or pure chaparral. They do not seem to affect the monotonous 

 stretches of greasewood at all. On several occasions the animals have been 

 seen in oak trees, in one instance about 30 feet from the ground. 



A common resort for chipmunks in the vicinity of Dudley was along 

 the rail fences bounding the ranches and bordering the hillside chaparral. 



