in the reconnaissance area (table 10). Twenty-six eagles were recorded on the 

 reconnaissance area during the winter 1977-1978 aerial survey, giving a density 

 of 1.2 eagles/100 square miles. 



Bald Eagle . The endangered bald eagle was most frequently observed along 

 the Missouri River where up to two individuals could be seen perched in cotton- 

 woods during the winter months. Bald eagles were also seen occasionally in the 

 vicinity of the proposed mining area, and two breeding-season records are note- 

 worthy, although they probably represent summer visitors rather than nesting 

 birds. 



Marsh Hawk . The marsh hawk was a fairly common summer resident through- 

 out the study area and was most frequently seen over moist drainage bottoms, 

 wet meadows and patches of western snowberry-prairie-rose. Two active nests 

 were located near the proposed mining area (table 10), and the distribution of 

 observations indicated that additional pairs nested in the mine study area. 



Osprey . As many as three pairs of osprey nested along the Big Dry Arm 

 in 1976 (Shupe p.c, Aderhold p.c). A nest located at the mouth of Nelson 

 Creek was contested by an osprey and a golden eagle in 1977, and was subsequently 

 abandoned by both (table 10). 



Prairie Falcon . The prairie falcon was an uncommon permanent resident in 

 the study area. In winter it was usually seen near grainfields where horned 

 larks provided an abundant food supply. An active nest was found on the face 

 of a steep butte less than 100 m (305 feet) north of the proposed mining area; 

 it is believed to have fledged four young in 1977 (table 10). The feeding 

 territory of this pair included most of the proposed mining area and probably 

 extended westward to Nelson Creek bay and east of the Waller Ranch. 



Peregrine Falcon . The endangered peregrine falcon was observed on four 

 occasions, all on or near the proposed mining area. A summer record is note- 

 worthy, but this species is not believed to breed in the area. Peregrine fal- 

 cons are occasionally seen in winter near Fort Peck Dam (Appendix J). 



Sharp-tailed Grouse . Distribution data were recorded for 1035 sharp- 

 tailed grouse observations during the study period (table 12). Average year- 

 long group size was five and group size showed little seasonal variation, although 

 lowest in summer and highest in winter. The largest group encountered numbered 

 32 birds and was seen during the winter of 1977-1978. 



Sharp-tailed grouse were distributed throughout the reconnaissance area 

 and the proposed mining area, where native grasslands and shrubby coulees re- 

 main. Ground observations indicated that sharp-tailed grouse were more abundant 

 in the northwest quarter of the reconnaissance area along Prairie Elk Creek, 

 and in the vicinity of the proposed mining area. Map 5 indicates locations of 

 the twelve dancing grounds located during this study, plus additional grounds 

 reported by Trueblood (p.c). Table 13 presents attendance at these grounds. 

 One dancing ground was located in the proposed mining area, but three addit- 

 ional grounds were found within the mine study area. Distribution of sharp- 

 tailed grouse was closely tied to the vicinity of leks and did not appear to 

 vary greatly throughout the year. The grouse were observed on the mining area 



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