172 ANIMAL LIFE IN THE YO SEMITE 



burrows in numbers, usually in groups of five and six. At Tenaya Lake 

 on July 29 the young animals seen were larger than those at the higher 

 stations. It is therefore probable that the young are born earlier at the 

 lower altitudes than at the higher levels. The record at Williams Butte 

 goes to substantiate this belief. Full size is not attained for some weeks ; 

 young weighing scarcely more than half as much as adults were taken at 

 Merced Lake August 31 and in Tioga Pass September 25, 1915. 



As early as July 26 small new burrows with mounds of earth at the 

 entrances were beginning to appear on Tuolumne Meadows. These were 

 evidently made by young which had been turned out of the parental 

 burrows to shift for themselves. 



When the young first go above ground they frisk about the entrance to 

 the burrow under the watchful eye of the female parent. In Lyell Caiion 

 on July 25, 1915, one of us came upon a single young animal running in 

 and about some rock crevices adjacent to the burrow at the side of the 

 meadow. The mother was standing guard, uttering her note, e-chert', every 

 few seconds. The observer 'squeaked,' whereupon the parent squirrel at 

 once rose upon her hind feet in the picket-pin position and uttered the 

 shrill piping warning call of the species ; the youngster promptly ran into 

 the burrow. The adult remained standing on her hind feet for 48 seconds, 

 then sank down on her haunches. 



A day or two later, another family group consisting of a female and 2 

 half -grown young, on Tuolumne Meadows, was studied at close range for 

 some time.^* At first the youngsters did not venture very far out of the 

 hole; and when they did they remained on the far side of their mother. 

 Later, they gained courage and came more into view, one being more ven- 

 turesome than the other. The mother stood much of the time in the picket- 

 pin position giving the e-cherV call. At each utterance her body was 

 shrugged up, the head and shoulders thrown forward and the tail given 

 an upward flip ; much effort seemed to be put into the production of this 

 note. In cases where families of 5 or 6 young were seen, they all sat close 

 about the entrance of the burrow and when frightened all attempted to 

 crowd into the hole at the same instant. One youngster, bewildered by 

 some horses, ran directly at one of our party and then escaped into a 

 shallow hole some distance from its home burrow. 



The Belding Ground Squirrel escapes the rigors of the Sierran winter — 

 when the temperature falls low and all the grasslands are blanketed in 



14 This was done by the method of direct approach. The observer garbed in dull 

 brown-colored outing clothes, started about 100 feet away and advanced slowly in a 

 direct line toward the squirrels. As he came closer his movements were made slower and 

 slower so as not to startle the animals. Sidewise movement was avoided in every possible 

 way. The squirrel, using monocular vision, was thus less able to appreciate his approach. 

 This method is very useful in getting close to birds or mammals in order to study or 

 photograph them. 



