226 CALIFORNIA FISH AND GAME 



places the snow was not much over eighteen inches in depth. I spent 

 several days on snowshoes on this winter range following both coyotes 

 and deer about so as to obtain first-hand information and facts relative 

 to- winter food habits and interrelation of the two species. At Crane 

 Flat in mid-January, I found the snow was slightly crusted and some- 

 what over five feet deep on the level. The mule deer seemed to realize 

 that they were at a decided disadvantage in deep, crusted snow and 

 although food, in the form of wind-broken branches, was plentiful on 

 the snow, they stayed out of such dangerous areas. Why? 



In the morning when the deer began to work up along the south 

 slopes where the snow was shallow, I found by tracking, and watching 

 with binoculars, that a pair of coyotes would slip around the hill, one 

 keeping from 50 to 70 yards above its mate. The coyotes usually 

 kept within sight of each other, and if hidden from view, each would 

 stop at 400-yard intervals and wait until the other coyote appeared. 



The lower coyote always kept about fifty yards ahead of its 

 mate. As soon as a deer was located, the lower coyote would attempt 

 to drive it up the hill and over the crest. If the deer tried to break 

 back, the second coyote would rush in so that the deer was pocketed 

 between the two animals. By thus keeping the deer between them, they 

 were able to drive young or inexperienced deer over the crest of the 

 ridge into deep-crusted snow, where the deer would break through 

 at every jump while the coyotes were able to run on top of the crust 

 and soon to capture and kill the deer that floundered helplessly about. 

 This and other similar experiences have convinced me that the presence 

 of natural enemies combined with unfavorable crusted snow may keep 

 deer out of areas which would otherwise be excellent winter range for 

 them. 



Russell (p. 35) points out that in Yosemite deer on the upper sum- 

 mer range often begin to seek lower range in advance of the fall snow- 

 storms. It has been my experience that deer are very well aware that 

 at high altitudes their danger from natural enemies is greatly increased 

 in the fall by the possibility of snow falling to depths sufficient to render 

 them helpless before the attacks of predators, and under such circum- 

 stances a downward migration before storms may be merely a pre- 

 cautionary movement to prevent possible disaster. It has been my 

 experience that some wise old doe, and not a buck, takes the lead in 

 sucli matters. Snowstorms of slight intensity usually cause a down- 

 ward migration, while heavy snowstorms, even if they come early in 

 the fall, cause mule deer to abandon their summer range. I had an 

 excellent demonstration of this fact at Lassen Peak in September, 1923. 

 "While camped at 6600 feet elevation on Warner Creek, I encountered 

 the heaviest September fall of snow that I have experienced anywhere 

 in western North America. It began to snow on September 23. At the 

 end of the three days' storm 26 inclies of snow lay on the level meadows. 



When the snow first began to fall, I found sixteen Rocky Moun- 

 tain mule deer within a distance of two miles of camp. The next 

 morning, with about a foot of snow on the ground, I traveled six miles 

 back and forth over the identical area and was unable to find any 

 deer at all. Not even a fresh track could be found. Investigation 

 showed that the deer began to abandon their summer habitat and started 

 at once toward their winter range, which lay across a high ridge, 50 



