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 × 10 × 8 inches outside and 6 × 5 × 4 inches inside, while the other measured 12 × 12 × 7 inches outside and 6 × 4 × 5 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 underground. The female and the male nests were in clay ground and the two colonial in sandy soil. The average depth of nests below the surface 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 (droppings 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
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