used (figure 28). Fall feeding observations did not differ from these results. 



During the winter of 1977-1978, sagebrush habitats appeared to become more 

 important to mule deer than during fall. Use of silver sagebrush/grassland and ' 

 silver sage habitats increased from 13% in December to 42% in January (figure 

 27). Grasslands accounted for nearly 20% of the observations each winter month. 

 In addition to these three habitats, feeding was observed in stubble fields and 

 low shrub coulees. Topography use also varied sharply between December and 

 January (figure 28). In December, 2% of the observations were of deer on ridge 

 tops. In January, the observations of deer on ridge tops had increased to 21% 

 of all observations, possibly because wind kept snow cover reduced in these 

 areas. Rolling terrain accounted for 54% of the observations in December and 

 decreased to 6% in January, while deer observed in coulees increased from 20% 

 to 48%. These shifts were probably related to worsening weather conditions. 



Data were obtained during this study on use of different slopes and aspects 

 by mule deer. Seventy-eight percent of spring observations and 83% of summer for 

 which slope was recorded were on slopes of 0-15% (table 20). Steeper slopes were 

 utilized more during fall and winter, when 30% or more of each season's deer were 

 observed on terrain of greater than 15% slope. No mule deer were observed on 

 slopes over 45%. During the spring and summer, respectively, 23% and 37% of 

 the 382 observations for which aspect was recorded occurred on east-facing 

 slopes. All southern aspects accounted for 44% of spring observations, while 

 only 20% of the summer observations occurred on these slopes. Limited data 

 for fall and winter revealed no trends. 



Mule deer were observed primarily between 5:00 A.M. and 9:00 A.M. during 

 the spring and summer. The deer were increasingly observable during afternoon 

 hours through fall and winter. 



Food habits of mule deer in eastern Montana have been well documented by 

 a number of studies (Egan 1971, Dusek 1976, Mackie et al.l977, Dusek 1977), and 

 observed seasonal habitat use on the study area reflected general known food 

 habits. Mule deer were mainly observed in sagebrush habitats, badlands, cou- 

 lees, and creek bottoms during winter when browse constitutes the bulk of their 

 diets. Deer were observed feeding on silver sagebrush, big sagebrush, horizontal 

 juniper. Rocky Mountain juniper, green rabbitbrush, prairie rose, dogwood, and 

 hawthorne. Use of succulent forbs and sprouting grass during spring is reflected 

 in the occurrence of most deer on grasslands. Mule deer moved from grasslands 

 to coulees during summer, probably as they sought succulent forbs. Mule deer 

 increasingly feed on browse during fall, and also use forbs and winter wheat 

 during periods of vegetational florishing. Accordingly, most mule deer were 

 seen on grasslands, stubble fields, and shrub habitats during fall months. 



Seasonal sex and age ratios calculated from classified observations of 

 mule deer are shown in Table 19. Fall data were used to calculate the best 

 ratio estimates, since only 20% of the winter 1977-1978 observations were class- 

 ified, and the observability of fawns was low during spring and early summer. 

 During the fall, 97 fawns: 100 females and 75 fawns: 100 adults were observed. 

 Production of 80-99 fawns: 100 females is rated "good" by Fish and Game Depart- 

 ment standards. Classified counts of mule deer by Fish and Game Department 

 personnel on McCone County trend units during 1972 and 1977 gave fawn: female 

 ratios of 117:100 and 133:100 respectively (Trueblood, 1976). Productivity 



106 



