22 

 mortality of 66% and 25% for juveniles and adults, 

 respectively (Schmutz and Fyfe 1987, Woffinden and Murphy 

 1989) . 



Selection of nesting sites was variable and, hence, 

 quite similar to that described by Myers (1987) for portions 

 of southwest Montana surveyed during 1985 and 1986. While 

 Myers (1987) found that Ferruginous Hawks most commonly 

 nested on the ground, I observed only 3 ground nests, 

 whereas, nests on rocky outcrops were by far the most common 

 nest type accounting for 53% of the nests observed. If only 

 the nests discovered in the actual surveys are included 

 (deleting the nests in the Centennial Valley) , only 2 nests 

 were located on the ground and outcrop-nests comprised 

 nearly 66% of the total. Additionally, I determined that 

 average slope upon which Ferruginous Hawks nested was 

 significantly greater than the slope described by Myers 

 (1987) (t = 3.232, 0.002 > p <0.001, n = 366). This 

 difference was likely due to the more broken landscape 

 surveyed during this study than during previous surveys in 

 southwest Montana. Additionally, the slope gradient nested 

 upon in southwest Montana was greater than nest slopes in 

 southeast Montana (Ensign 1983). However, like Myers (1987) 

 I determined that the majority of nests were located on the 

 upper portion of slopes which may allow hawks an 

 unobstructed vantage point and an efficient departure route 

 from the nest. 



A southern nest exposure such as I observed in this 

 study, as well as in other studies (Smith and Murphy 1982, 

 Ensign 1983, Myers 1987), has been interpreted to indicate a 



