ABSTRACT 



From June to August 1992, 42,890 ha of public and private 

 land were surveyed in Beaverhead and Madison counties of 

 southwest Montana for the presence of Ferruginous Hawks. 

 Fifty nests were located, including 16 active nests (15 

 previously undocumented territories) . With the addition of 

 these active nests, the surveyed areas of southwestern 

 Montana contain at least 132 active territories. Hawks 

 chose a variety of substrates upon which to nest, primarily 

 placing nests upon rocky outcrops (51.6%) in this high 

 elevation population (x = 1888 + 178.5 m) . Nests were 

 located near the apexes (65.39 + 17.87%) of steep slopes 

 (62.76 + 40.15%) which predominantly exhibited a southern 

 exposure (190.84 + 62.45°). Habitat within 100 m of 

 Ferruginous Hawk nests consisted of approximately equivalent 

 proportions of grassland and shrubland, whereas grassland 

 constituted over 50% of the vegetation within a 1.6 km 

 circle centered at the nest. On average, territories 

 contained 1.31 + 0.92 alternate nests and active territories 

 were separated by a mean of 1911 m (SD = 659.2 m) . Density 

 of breeding Ferruginous Hawks was highly variable throughout 

 the study area ranging from to 0.10 active territories per 

 square kilometer (x = 0.04 + 0.04 active territories/km^). 

 Fifty percent of the active and inactive nests were observed 

 in the Sagebrush Steppe Association, whereas the Foothill 

 Prairie Association contained 43.8 and 23.5% of the active 



