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species was a "sununer visitor, everywhere abundant," and in fact was the most 

 common hawk in eastern Montana. He also stated that all birds were gone by 

 the middle of October. The wintering observations which were recorded for 

 this species during this study were probably related to the mild open winter. 



Great Horned Owl (Bubo vivginianus) - Great horned owls were commonly observed 

 "on the area in the sage-grassland and badland types. In addition, seven active 

 nests were located in both 1979 and 1980 in a wide variety of situations (i.e. 

 old house, cliffs, old red-tailed hawk nest, ledge in grassland coulee, etc.). 

 Wintering by this species was also known to occur on the area and in view of 

 this fact, and the wide variety of nest sites employed, it was listed as being 

 common. Cameron (1907) stated that the horned owl was a common and year-long 

 resident of this area. 



Burrowing Owl (Athene auniaularia) - In 1980 two active nests of this species 

 were located in the prairie dog towns of the area. Nests were recognized by 

 observing the adults in the vicinity, and by scattered broken cow chips around 

 the burrow entrance. Bent (1938) stated that the nests of this species were 

 profusely lined with finely chipped, dry horse or cow droppings and that this 

 lining, which usually showed at the entrance of the burrow, seemed to be char- 

 acteristic of occupied nests. In addition to the two nests, approximately 

 six observations of other birds occurred each year and it is probable that more 

 nests were located on the area. Nichols (pers. comm.) also indicated that the 

 study area was used for breeding by this species. All observations of burrowing 

 owls during this study occurred on or immediately adjacent to prairie dog towns 

 in the sage-grassland type. Because sightings of this "special interest or con- 

 cern" species were not numerous it was listed as uncommon for this area. Histor- 

 ically, it was listed as a "common resident" (Cameron 1907) but no evidence of 

 wintering by this species was observed during this study. The species is 

 generally migratory in the northern parts of its range (Bent 1938) . 



Short-Eared Owl (Asia flammeus) - This common species was observed most often 

 in the grassland type and in grassy areas in the sage-grassland type. Although 

 no nests were located, several fledgling young were seen and breeding undoubtedly 

 occurred on the study area. Approximately 30 observations of this species 

 occurred in 1979 while in 1980 that number dropped to only two. Again, it is 

 possible this was a reflection of the adverse effects of the drought. This 

 species was known to winter on the area and historically Cameron (1907) listed 

 It as an "erratic winter visitor, tolerably common some winters and in others 

 not observed." It was interesting to note that he makes no mention of breeding 

 or summering. In fact, he states that May 7 is the latest data he observed 

 this species. 



BREEDING BIRD SURVEY 



A summary of the results of the breeding bird surveys for both years is 

 presented in Table 3. Individual transect results are presented in Appendix 

 Tables 11-18. In 1979 the sage-grassland type had the highest average density 

 of breeding pairs (146.8 per 100 ha), while the creek type had the greatest 

 diversity^ of breeding pairs (14 species). During 1980, however, the creek 



^Diversity is used in this report as a synonym for the "numbers of species." 



