Sample abundances were significantly and positively correlated with big sage- 

 brush badlands (p<.001), and were significantly and negatively correlated with 

 cultivation (p<.001). | 



Field Sparrow . The field sparrow reaches the western edge of its range in 

 this part of Montana (Skaar 1976). This eastern species was typically observed 

 in fairly steep grassland habitats with scattered sagebrush plants along the 

 edges of the Missouri River and lower Prairie Elk floodplains; this is reflected 

 in its sample abundances curves (figure 23), which show it to be most common 

 along these two routes. A few were heard along the Circle route in July; none 

 were encountered along the Flowing Well or Dreyer Ranch routes. Sample abun- 

 dances were significantly and positively correlated with horizontal juniper and 

 bluebunch wheatgrass, silver sagebrush, and tall shrubs and trees (p<.001), and 

 were significantly and negatively correlated with time and big sagebrush bad- 

 lands (p<.01). 



Chestnut-Collared Longspur . The chestnut-collared longspur was a close 

 associate of the horned lark, with which this common breeding species shared a 

 similar habitat characterized by rolling upland blue grama-needle-and-thread 

 grassland, heavily grazed and often with scattered patches of little bluestem. 

 Owens and Myers (1973) also found this species to be closely associated with 

 overgrazed grasslands. Flocks arrived in the study area in early April and re- 

 mained through September. Highest sample abundances by far were found for the 

 Circle route during all months and this species may be considered an indicator 

 for grassland habitats along the Circle route (figure 24). Intermediate numbers 

 were encountered along the Dreyer Ranch route, and very few were encountered along 

 the remaining routes. A breeding density of 20 pairs/km^ (twenty-six pairs per 

 square mile) was determined for the needle-and-thread-blue grama grassland cen- i 

 sus plot, which appeared to represent optimal habitat in the study area. Sample 

 abundances were significantly and positively correlated with grassland (p<.001) 

 and significantly and negatively correlated with sagebrush, badlands (p<.001), 

 horizontal juniper, and trees and tall shrubs (p<.01). 



Merriam's Shrew . A single specimen of Merriam's shrew -- the only soricid 

 taken during this study -- was taken in a pitfall trap in a dry, rocky horizontal 

 juniper habitat within the proposed mining area. While the study area is within 

 the reported range of this species, this capture is noteworthy, since very few 

 specimens have been taken in Montana. The apparent rarity of this shrew is 

 likely an artifact of inadequate pitfall trapping efforts in Montana. 



Desert Cottontail . The desert cottontail was most abundant in winter in 

 coulee and badland habitats, and in summer in sagebrush flats, sagebrush-grass- 

 lands, and snowberry-rose. Numbers of cottontails seen during three runs of the 

 lagomorph survey routes (map 3) are presented in table 18. Numerous local res- 

 idents noted that lagomorph abundance was particularly low during the summer of 

 1977; therefore, the numbers seen probably represent a minimal abundance index. 



White-tailed Jackrabbit . The white-tail jackrabbit was far more abundant 

 on the lagomorph survey routes than the desert cottontail (table 18), and at- 

 tained moderate to high densities on and near the proposed mining area. However, 

 more cottontails than jackrabbits were generally seen along the roadside wild- 

 life survey routes (table 9). Preferred habitat was open grassland, silver sage- 

 brush flats, and sagebrush-grassland. 



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