GROUND SQUIBB ELS 171 



the margins of the meadows. Those squirrels which live in the bunch-grass 

 areas at or above timber line make their burrows, of necessity, in the granite 

 soil, A typical meadowland burrow at Snow Flat was opened and studied 

 by the authors on June 28, 1915. This burrow was close to the bank of a 

 small creek, which meandered through the meadow, and 'was near a large 

 granite boulder. The ground was heavily matted with grass roots to a 

 depth of 1% inches (45 mm.) and all the tunnels had been excavated below 

 this mat. The whole tunnel system was remarkably level, unlike those of 

 the California Ground Squirrel in the lowlands; but this may have been 

 conditioned by the nearness of the creek and of the water table. Two 

 short, deeper tunnels which were found may have been prospects toward 

 a deeper system which would have been excavated later in the season. There 

 was melting snow about the meadow and the ground was quite Avet on the 

 date of our study, especially below the level of the tunnels laid open. The 

 presence of this extreme amount of moisture may have acted to deter the 

 squirrel from going any deeper. 



The total length of all the tunnels in this system was 53.3 feet (16,25 

 meters) and the average tunnel diameter 2 inches (52 mm,). The total 

 amount of earth excavated was therefore 2010 cubic inches — 8.7 gallons 

 of earth, or nearly enough to fill two 5-gallon oil cans. Yet there were no 

 mounds of earth at the entrances to the burrow. The soil had either been 

 pushed into the creek or else washed away by the summer rains and melting 

 snow water. 



This burrow system contained no well constructed nest; but in one 

 place there was some grassy material, either the remains of an old nest 

 or, more likely, the beginning of a new one. The inhabitant of this burrow 

 was a female which would have given birth to young, within two weeks 

 probably. 



One burrow of this species was noted at the base of a lodgepole pine. 

 In this case there was a mound of earth at the entrance. 



The young of the Belding Ground Squirrel are born about the first of 

 July, there being, so far as all ovir evidence shows, but one brood per year. 

 Yet a pair was seen in what looked like a mating pursuit as late as July 13. 

 The number of young was ascertained definitely in only one case, that 

 of the female containing 5 embryos, at Snow Flat, June 28. A female 

 obtained July 2 east of Porcupine Flat had evidently just given birth to 

 6 young. In females taken on July 8 and 21, 1915, the mammary glands 

 were functional. The young, when they first appear above ground, are 

 scarcely more than one-third grown. The first young were noted in 1915 

 on July 25. But near Williams Butte three young only a third grown were 

 seen on June 28 (1916). At the end of July (27-31) in 1915, in Lyell 

 Caiion and on Tuolumne Meadows, young were out at the mouths of 



