Upland game birds found in the study area were the sharp-tailed grouse, 

 sage grouse, ring-necked pheasant, and gray partridge. Twelve sharp-tailed grouse 

 and ten sage grouse leks were located during this study. The proposed mining area 

 appears to provide favorable habitat only for sharp-tailed grouse. 



The sagebrush census plot was found to support the greatest number of breed- 

 ing bird species and the greatest total density of breeding birds, although high- 

 est total biomass and species diversity were found on the coulee shrub plots. The 

 horned lark and western meadowlark were the predominant breeding bird species in 

 the study area. Most breeding birds are summer residents rather than yearlong 

 residents. Migrants and winter residents were a minor component of bird communities 

 at all seasons. Most breeding bird species are omnivorous or insectivorous ground 

 and brush foragers; raptorial and herbivorous species are relatively uncommon year- 

 long. 



Analysis of the roadside survey data revealed distinct seasonal patterns of 

 sample abundances for individual species as well as of species number, species 

 richness, species diversity, species evenness, and community dominance. These 

 data allowed an ordination of the five routes from highest to lowest diversity. 

 Fifteen indicator species (that is, those which consistently showed highest sample 

 abundances for a single route) were identified. The data analysis indicates that 

 the roadside routes were effective in sampling 74-91% of the total number of breed- 

 ing species present. 



Deer mice were the dominant small mammals in most habitats and showed broad- 

 est habitat niche and highest degree of niche overlap. The western harvest mouse 

 attained co-dominance in the silver sagebrush live-trap plots and dominance in two 

 of the snap-trapped habitats. Shrub habitats, especially tall coulee shrub, were 

 found to be most productive and/or diverse of those sampled, but were of limited 

 extent. Seasonal changes in small mammal density were examined on the live-trap 

 grids. Black-tailed prairie dog towns were abundant near the southern end of Big 

 Dry Arm of Fort Peck Reservoir but scarce in upland habitats, although one town 

 was found near the proposed mining area. Black-footed ferrets may occur in the 

 former area, but are unlikely on the latter due to the relatively small size and 

 isolation of the town. 



Big game mammals found in the study area are the mule deer, white-tailed 

 deer and pronghorn antelope. Mule deer were widely distributed in all habitats, 

 but showed a perference for badlands, coulees and tall shrubs, especially during 

 summer and fall. Minimum density estimates for mule deer were 0.10 deer/km^ 

 (0.25/mi2) in the entire study area and 0.22/km2 f0.56/mi2) for the 

 mine study area. Ratios of 87 fawns; 100 does and 20 bucks; 100 does were obtained. 

 White-tailed deer were less frequently seen than mule deer, and preferred cultivated 

 grassland and low shrub habitats of flat to rolling topography with trees or tall 

 shrubs nearby for escape cover. The minimum density estimate for the entire study 

 area was 0.1 deer/km^ (0.2/mi2), the proposed mining area apparently 

 provided poor habitat. Production ratios of 74 fawns; 100 does and "20 bucks: 100 

 does were obtained from fall data. Pronghorn antelope were also widely distri- 

 buted, but concentrated in areas of rolling sagebrush in winter. Rolling sage- 

 brush, grassland, and cultivated fields were preferred yearlong, A fall minimum 

 density estimate of 0.3 pronghorn/km^ (0.7/mi-) was obtained for the entire 

 study area; productiv ity ratios of 80-90 fawns; 100 females and 40-60 males; 

 100 females were calculated from summer and fall data respectively. ^ 



202 



