In summary, mule deer in the study area are largely found in association 

 with rough breaks and coulees. The overall minimum density estimates can be 

 misleading since habitat quality if not uniform over the entire area. During 

 all seasons the mule deer population was densest in the southwest quarter of 

 the reconnaissance area, where more broken topography was dominant. 



During spring, summer, and fall, the proposed mining area apparently pro- 

 vides good habitat for mule deer, especially in the heavily dissected northern 

 half. With the onset of winter, however, the deer move to lower elevation cou- 

 lees and creek bottoms to the north, west, and south of the proposed mining area. 



White- tailed Deer . Data were recorded for 938 white-tailed deer obser- 

 vations representing 218 groups during the study period (table 22). Average 

 group sizes decreased steadily from 10 during January 1977, to a low of two 

 during July (figure 26). Throughout fall and winter, the deer tended to 

 gather in larger groups, having an average size of six during January 1978. 

 The yearlong average group size was four, and the largest group encountered 

 numbered 51 during the winter of 1977-1978. 



Although during the study period only 938 whitetails were observed, while 

 3486 mule deer were observed, records of hunter harvest in the reconnaissance 

 area show that approximately half of the annual deer kill is white-tailed deer 

 (Trueblood 1976). This indicates that although white-tailed deer are not as 

 observable as mule deer, they probably occur in substantial numbers on the re- 

 connaissance area. 



Limited data were obtained for white-tailed deer, largely because of their 

 nocturnal habits and preference for wooded or shrubby habitats where observ- 

 ability is low. Observations indicated these deer were most numerous along the 

 Missouri River, Prairie Elk Creek, and Horse Creek (maps 11-13). White-tailed 

 deer occurred where cultivated fields were located near brushy coulees, creek 

 bottoms, and cottonwood groves which provided cover. The deer population ap- 

 peared to be densest in the southeast quarter of the reconnaissance area during 

 the winter aerial census of 1977-1978. General distribution appeared to remain 

 fairly constant throughout the year. 



No white-tailed deer were seen on the proposed mining area during winter 

 or fall, and only one sighting during spring and two during summer were made 

 within its boundaries. Scattered observations were made during summer and fall 

 within five miles of the proposed mining area near the Dreyer Ranch and the 

 head of Horse Creek. 



A total of 334 white-tailed deer was observed in the reconnaissance area 

 during the winter of 1977-1978 aerial survey, giving a minimum density estimate 

 of 0.1 deer/km2 (0.2/mi^). 



Vegetation types and topography were recorded at 94% of the white-tailed 

 deer observation locations. Forty percent of the observations were of feeding 

 deer. Due to the limited number of sightings, vegetation and topography were 

 analyzed for seasonal rather than monthly trends. Flat to rolling cultivated 

 and grassland habitats accounted for the majority of observations during all 

 seasons. The importance of trees yearlong is underestimated by the data due 

 to low observability in this habitat (figure 30; see also Appendix K) . 



109 



