113 



to concentrate on meslc areas. Competition with livestock may have 

 been a significant factor in the observed change in habitat use 

 between years. Use of creek bottom types increased again in 

 summer 198I when livestock were more dispersed. In addition to 

 providing succulent forage and water, favorable thermal conditions 

 in mesic creek bottom habitats provide relief from high temp- 

 eratures for deer. 



Activity : Mule deer activity at time of observation is presented 

 in Table 50. The largest proportion of deer were standing or 

 feeding when first seen during all seasons except winter, when 

 a large proportion of animals were bedded. Feeding activity at 

 time of observation was most prevalent in spring and least common 

 in winter. 



Use of topography: Deer used the rugged mesa-butte features most 

 during fall and winter (Table 51). Dissected mid-slopes were most 

 heavily used in early spring when new plant growth appeared. Use 

 of alluvium/terrace and flood plain categories was highest during 

 summer and fall, as deer use of creek bottom habitats increased. 



Use of exposure : The percentage of mule deer observations on 

 flat terrain was highest during summer and fall seasons, coin- 

 cident with high use of mesic lowland habitats (Table 52). Deer 

 were observed on every aspect during all seasons. Heavy use of 

 the northeast exposure occurred during the warm and dry spring of 

 1981. 



Use of slope ; Use of flat and gentle terrain categories was 

 greatest during summer and fall seasons (Table 53). Use of 

 steeper terrain features was highest in winter, when mule deer 

 utilized ponderosa pine habitats on ridges and hillsides. 



White-tailed Deer 



Seventy-nine individual white-tailed deer were observed on the 

 study area during the study period (Figure 62). Most observations 

 were associated with deciduous habitats and hayfields along Little 

 Pumpkin Creek, in the southern portion of the study area. 



Pronghorn Antelope 



Population characteristics : During the study period 4,046 

 antelope were observed on the Foster Creek study area (Table 54). 

 Mean group size was smallest during spring and summer, peaking at 

 26.3 in winter. Mean number of observations per hour of aerial 

 survey was highest during fall surveys (46.1) (Table 47). 



Summer population structure is presented in Table 55. Fawn/doe 

 ratios between 48.7:100 and 50.7:100 indicate rather poor 

 reproductive success both years for this herd. Population trend 

 surveys covering all of hunting district 74l between 1972 and 

 1977 indicated fawn/doe ratios between 55:100 and 85:100 for this 

 area (Wentland 198I). The population is on its way to recovery 

 following a decline during the severe winters of 1977-78 and 1978-79 

 (Wentland 198I). 



