greater frequencies and longer durations of sub- 

 zero and subfreezing temperatures, deeper ground- 

 surface snow for longer periods, higher relative 

 humidity, more effective precipitation, and less 

 wind than the other exposures. 



Of the 600-odd deer observed during the study 

 73 percent were in shrub types, 13 percent in open- 

 timber types, 11 percent in drainage areas, and 3 

 percent in heavy timber areas. Of the total num- 

 ber seen, 70 percent were observed on the upper 

 half of the exposures involved. 



Results of this and associated research conducted 

 concurrently by the Colorado Game, Fish, and 

 Parks Department have provided new and rela- 

 tively precise information for more effective man- 

 agement of mule deer winter range, the key prob- 

 lem in maintaining herds of the most important 

 big-game species in the West. 



Ecology of the Middle Fork mule deer winter 

 range. — The Idaho Unit's investigation of this 

 critical winter range on the Salmon River revealed 

 an area of unstable soil on relatively steep slopes. 

 Downward soil movement is caused by runoff, 



gravity, and big-game concentration on the area 

 during the winter months, abetted by relatively 

 thin density of the principal shrubs: bitterbrush, 



27.7 percent; gray rabbit brush, 23.3 percent; big 

 sagebrush, 19.3 percent; and slender eriogonum, 



14.8 percent. Bitterbrush provided only 9 percent 

 of the live perennial vegetative cover; big sage- 

 brush, 5.4 percent; gray rabbit brush, 4.3 percent; 

 and slender eriogonum, 4.3 percent. There are 

 approximately 444 shrubs per acre, of which 69 

 are bitterbrush plants. Utilization of bitterbrush 

 during the mild winter of 1961-62 was 56 percent 

 of the annual growth. 



The inaccessibility of the critical Middle Fork 

 range makes adequate harvests of mule deer diffi- 

 cult. During the early part of the hunting season 

 (September 15-Xovember 15), deer remain high 

 and scattered in precipitous terrain and descend to 

 lower elevations in numbers only during the third 

 month of the season. Productivity studies for 

 both the herd and the range have provided the 

 Fish and Game Department and the U.S. Forest 

 Service with basic management information. 



The expanding reindeer herd on St. Matthew Island in the Bering Sea provides the basis for a range-use study by 

 the Alaska Unit. The herd has increased from 29 animals at the time of release in 1944 to 6.000 in 1963. (Photo by 

 David R. Klein) 



