202 



support any major portion of an eagle territory. All fall and ^ 

 winter observations of golden eagles were mapped as "nonbreeders" 

 although some of these may have been resident eagles from 

 surrounding territories. The reason why territorial golden 

 eagles are absent on the study area, yet present in adjacent, 

 similar habitat is not known. The absence of a sufficient 

 prey base may be a factor. Prairie dogs, formerly abundant 

 on the study area, have all been eliminated. They are often 

 a major food source for golden eagles. 



Bald eagle - As mentioned above, bald eagles occur throughout 

 the winter, primarily along the Tongue River. They were 

 present from about the end of October to mid-late April. 



Osprey - Several ospreys were sighted along the Tongue River, 

 They were all assumed to be migrants. The nearest osprey nest is 

 located on the Tongue River Reservoir, about 20 miles to the south. 



Prairie falcon- One orairie falcon aerie was located in the study 

 area. It was active both summers of the study. Prairie falcons 

 were sighted over the study area fairly far from the known nest. 

 It is not known if these were members of that pair, visitors 

 with aeries outside the study area, or territorial non-breeders. 

 Another cliff in the study area with suitable potholes was 

 checked for falcons, but none were found. This cliff was 

 suspected to have been occupied by great-horned owls. Most of 

 the cliffs in the study area did not have suitable potholes (,, 

 or ledges for nesting prairie falcons. 



Merlin - One merlin, assumed to be a migrant, was observed. 

 Suitable habitat for nesting merlins does occur in the study 

 area, so future nesting is a possibility. 



Saw-whet owl - This species was not observed in the study area, 

 but was suspected to occur in the marsh at the mouth of Cook 

 Creek. Suitable habitat for them is also found on the upper 

 ends of Bull Creek and Cook Creek. 



Other Special Interest Species 



The Brewer's sparrow, field sparrow, and upland sandpiper are also 

 listed by Flath (198I) as species of special interest or concern. 

 All three were suspected breeders on the study area. Upland sand- 

 pipers were commonly observed on the ridge near sharp-tailed grouse 

 ground number 2 (Figure 89). Brewer's sparrows were common in 

 sagebrush habitat throughout the study area. One territorial field 

 sparrow was observed on Coal Bank Creek during the breeding season. 



The double-crested cormorant and Lewis' woodpecker are listed as 

 migratory bird species of high federal interest for the Powder River 

 Coal Region. The double-crested cormorants were visitors from a 

 rookery located on the Tongue River Reservoir. Lewis' woodpeckers 

 were occasionally seen on Cook Creek near the reservoir in the 

 northwestern corner of the study area. 



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