232 AMMAL LIFE IX THE YOSEMITE 



Nevada -was the Sierra Mountain Hheep ; and in the intervening middle 

 altitudes was the Mule Deer. Now all save the last have vanished, probably 

 never to return; but the Mule Deer is still present over most of its early 

 range, though doubtless in but a fraction of its original numbers. 



Mule Deer are most frequently seen by foot travelers in the summer 

 on and near the trails above the rim of Yosemite Valley, but autoists en 

 route to or from the Valley, especially during the fall months, often see 

 them along the roadsides. The deer range over practically all of the hilly 

 and mountainous country in the Yosemite region, from the westernmost 

 extension of the brush belt bordering the San Joafpiin Valley east over 

 the crest of the Sierra Nevada to Mono Valley. They are not uniformly 

 distributed over the whole area, however, nor do they occur in all portions 

 of it at all times of the year. A small number remain in the Upper Sonoran 

 chaparral belt of the western foothills during the summer season, and a 

 few also occur on the ea.st base of the Sierras, but the great majority 

 of the animals are to be found at this time in the brush country of the 

 higher mountains, in the Transition and Canadian life zones, at altitudes 

 of from 3500 to 8500 feet. Some wander up toward timber line, our highest 

 record being 10,600 feet, near Fletcher Lake, In winter they descend to 

 lower altitudes, there being thus a distinct migratory movement twice each 

 year. Those on the Avestern side of the mountains migrate to the region 

 from Bridal Veil Meadow (3900 feet) and the southern slope of Pilot Peak 

 (at 4500 feet) west to Forty-nine Gap (1500 feet), while the animals on 

 the east slope cross Mono Valley to the country east of Mono Craters. Indi- 

 viduals occasionally range on the west as low as Snelling. in the Merced 

 River bottom well beyond the westernmost foothills. 



The two factors controlling the local distribution of deer in the Yosemite 

 region are the presence of the right kind of brush for food and shelter, 

 and the absence of deep snow. Deer depend chiefly on certain brush plants 

 for their sustenance. When these shrubs are covered with snow, or 

 surrounded by snow more than 18 inches deep, the animals are unable to 

 feed. Their altitudinal migrations seem to be controlled entirely by snow- 

 fall ; they ordinarily remain in the high mountains in the fall until the 

 first snow of the sejison sends them downhill and concentrates them along 

 the western boundary of the Park. As a rule, they do not stay where th«' 

 snow lies to a depth of more than li/o feet, but, other conditions permitting, 

 they do remain just below this level. Their numbers in the most favorable 

 localities may tend to become larger than the supply of forage will sup|)orf. 

 and then competition forces many of them still lower down, into the foot- 

 hill chaparral belt entirely west of the Park boundary. The migrant (l(H>r 

 go farther westward than do those animals which reside throughout the 

 vear in the footliills. Large inimlxM's of deer from the northern part of 



