624 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



BUTEO BORE A LIS, (Gm.) Vieill. 



Eed-tailed Buzzard; Hen Hawk. 



I frequently observed this Hawk in different portions of Iowa, Kansas, 

 Minnesota, and Dakota ; but, in most portions of the last-named Terri- 

 tory, it is not nearly so abundant as the next species {B. swainsoni). 

 The only individual noticed during my connection with the Survey was 

 shot on the Mouse Eiver, where B. swainsoni was the prevailing form. 



List of specimens. 



BUTEO SWAINSONI, Bp. 

 Swainson's Buzzard. 



Yery abundant in Northern Dakota and Montana, where, I may say, 

 I saw it almost daiiy each season. None of the Hawk tribe, in fact, were 

 more numerous, excepting the Harrier and Sparrow-hawk. In this 

 part of the country, neither the Eough-legs nor the Red-tails are com- 

 mon, and Swainson's Buzzard chiefly represents the genus. The bird 

 may consequently be studied satisfactorily, both with regard to its 

 habits, and to those great changes of plumage which, before they were 

 understood, were so perplexing, and caused several nominal species to 

 be proposed. 



Swainson's Buzzard may be found anywhere in the region indicated. 

 When about to alight on the ground in open country, it generally takes 

 advantage of some little knoll as an observatory whence to watch for 

 the gophers. But it gives the preference to wooded regions, and is 

 always most numerous in the vicinity of streams fringed with trees. The 

 nest is usually placed in trees, sometimes in shrubbery, but when both 

 these fail, is placed on the brink of a cut-bank, or on some shelf pro- 

 jecting from its face, like those of most other Hawks under the same 

 circumstances. These ground nests are apt to be less bulky and elab- 

 orate than those constructed in trees ; and there is always a wide lati- 

 tude in this respect, according to the precise character of the site selected. 

 During the first season I was too late for eggs, when I first met with 

 the birds, but discovered several nests in the timber along the Mouse 

 River. The only one I found with anything in it contained two half- 

 fledged young ; it was very untidy with the scurfy exfoliation from the 

 growing feathers of the youngsters, their excrement, and remains of tbeir 

 food in the shape of gophers. Previous to this time, in July, an un- 

 fledged yoiiDg was brought to me, and early in August I possessed a 



