THE GROUND SQUIRRELS OF CALIFORNIA. 



617 



were large and evidently of considerable age, since the foxtail blades 

 and stems composing the nests were old and broken up into short bits. 

 One of these nests measured 12 x 10 x 8 inches outside and 6x5x4 

 inches inside, while the other measured 12 x 12 x 7 inches outside and 

 6x4x5 inches inside. The third nest was old, being merely a flat mat 

 of trampled down bits of foxtail stems. 



The nest of the female (fig. 10) was 30 inches below the surface of 

 the ground. The nest of a male was 28 inches below the surface, while 

 the two used nests in the colony burrow were 20 and 24 inches under- 

 ground. The female and the male nests were in clay ground and the 

 two colonial in sandy soil. The average depth of nests below the sur- 

 face of the ground, taking into account all of the nests found, was 30 

 inches. 



Contrary to general belief, we have found ground squirrels to be 

 very cleanly animals about their nests and burrows. No feces (drop- 

 pings or dung) were found in any nest. Such material was found 



Fig. 11. Nest and small young of "digger" squirrel after removal of the female. 

 Same nest as shown in Fig. 10. 



heaped up in piles in special chambers usually just off the main run, but 

 within easy reach, 18 to 24 inches, from the nest. These sumps were 

 lower than the nests and were sometimes nothing but old nest cavities 

 which had been dug somewhat deeper than they had formerly been. 

 In the burrow of a male squirrel, a pile six inches in diameter and 

 two inches high, of feces soggy with urine was found in a sump slightly 

 below and fourteen inches distant from the nest. Female squirrels 

 appear to be more particular in this regard than the males, in that the 

 sump is farther removed from the nest. 



The nest that contained the four young squirrels (see fig. 11) was 

 alive with fleas, which swarmed over the helpless young. These fleas 

 persisted in remaining in the nest for three days after the young 



25 



