smaller drainage bottoms provided succulent forage longer than 

 did other areas. Forbs and shrubs under the Douglas-fir 

 canopy on most north-facing slopes not only were subject to 

 less evapotranspiration stress during the heat of summer, but 

 were protected from the earliest killing frosts of autumn by 

 a temperature-moderating effect of forest canopy. Those deer 

 living adjacent to the Missouri River bottom made more use of 

 the river riparian type during autumn for similar reasons. 



During winter, forage was less of a driving force in 

 determining movements and habitat use. In the northern United 

 States and on this area, most of the forage available to deer 

 during winter is of only maintenance guality or poorer (Bucsis 

 1974, Short et al . 1974, Mautz et al . 1976, Wallmo et al. 

 1977, Mautz 1978). Plant species making up the bulk of the 

 winter diet on this area (big sagebrush and Rocky Mountain 

 juniper) are abundant and ubiguitous . During mild or "normal" 

 winters, deer can find adeguate guantities of most winter 

 forage almost everywhere. However, rabbitbrush, a preferred 

 species, was primarily available at the edge of ridges in the 

 ecotones between sagebrush and pine and Douglas fir types and 

 when snow depth was greater than about 4 5 cm, most rabbitbrush 

 was unavailable. 



Although snow depth was reduced on the south- and 

 north-facing slopes deer moved to during severe winters, 

 forage availability did not appear to be the factor governing 

 those movements. The south-facing slopes on the severe winter 

 areas were usually either the pine- juniper-shale or greasewood 

 and shale-longleaf sage vegetation types. Those types were 

 the poorest of all types in forage guantity and guality 

 (Tables 3.2 and 3.3). Use of the auxiliary winter areas 

 provided deer with ease of movement and escape from predators, 

 warm sites on sunny days on the south-facing slopes and 

 relatively warmer sites on the timbered north-facing slopes at 

 night and during cold, windy days. 



During spring, deer made the greatest use of the open 

 sagebrush-grassland type and least use of the dense Douglas 

 fir types. Such use was related to the greater availability 

 of new green forbs and grasses in the open types. It reguired 

 movement of only 100-200 m to open areas rather than major 

 movements to entirely new areas of use. 



The home range of males should also contain adeguate 

 resources for survival, but the reguirements of males differ 

 from those of females (Verme 1988) . Our data indicated that 

 males occupied lower guality habitat than productive females 

 did, at least during summer and early autumn (Chapter 9). 

 Data on social structure, distribution, movements, and habitat 

 use indicated that males, especially during the fawn-rearing 

 period, spend most of their time on sites not occupied by 



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