MOUNTAIN BE AVER 157 



Porcupine Flat; and finally a colony of Aplodontia was discovered at an 

 altitude of 10,000 feet on the slope of Kuna Crest in the head of Lyell 

 Cafion, (See fig. 21.) The lowest record, altitudinally, was made at 

 Gentrys, 5800 feet, Avhere, in the fall of 1915, tunnels were found in fair 

 numbers though none of the animals was obtained. 



The 'colonies,' or at least the series of workings so called, are in many 

 cases of considerable extent. In one place an area estimated at 50 by 100 

 yards was occupied; other colonies were of somewhat less extent. The 

 number of holes in a colony is large, 20 to 30 being noted in one locality 

 on Snow Creek. The population in any one limited series of burrows 

 consists usually of not more than two adults, comprising a pair. If these 

 are trapped out, several days intervene before animals from neighboring 

 burrows move in, to occupy the deserted ones. 



The colonies are in most cases fairly well sheltered from view by the 

 vegetational cover of the stream banks. But in early spring, just after 

 the snow has melted off and before the willows and dog^vood are leaved 

 out, the burrow openings may be readily seen. 



Aplodontia seems to be active, even at the higher levels, throughout the 

 year. There are no data to indicate that the animals hibernate, while much 

 circumstantial evidence points toward regular active life throughout the 

 winter season. In many places we saw willow branches and small conifer- 

 ous trees which showed signs of beaver activity as high as 5 feet above the 

 ground. This animal is not known to climb to any extent, so the conclusion 

 seems justified that it comes up through the snow, even out on the surfa.ce 

 of the snow, and nibbles at the twigs then within easy reach. Along the 

 west fork of Indian Canon (above Yosemite Falls) a quantity of 'hay' 

 was observed, consisting of a narrow-leaved lupine (Lupinus longipes) 

 which had been cut green and piled and cured on dry masses of drift 

 material. This 'hay' when seen on October 30, 1915, was nearly dry. In 

 each pile the butt ends of the stems usually lay in one direction, toward 

 the entrance of the adjacent burrow. Whether this material was for winter 

 food, as with the cony, or for a dry and warm winter nest below-ground, 

 was not ascertainable. 



Aplodontia feeds upon most of the plants growing in the vicinity of 

 its burrows. At Chinquapin the following plants gave evidence of being 

 used by the animals: Azalea (Rhododendron occidentale), the commonest 

 plant and used very much ; hazel, common but little used ; Sierran currant 

 (Ribes nevadense), common, and many cuttings seen; creek dogwood 

 (Cornus pubescens), common, many cuttings; wild cherry, fairly common, 

 a few cut twigs seen; snow-bush (CeanotJius cordidatus) , abundant at 

 edges of thickets and occasionally used; chinquapin, abundant at edges 

 of inhabited thickets and much used in places; incense cedar, few young 



