SWAINSO]?^'S HAWK 233 



ward. Mr. Skinner's earliest date for the last one seen in Yellow- 

 stone Park is August 23, and his latest certain date is September 20. 

 Many observers have noted the spectacular fall flights of these 

 hawks, constantly passing in small bands, or in flocks of hundreds. 

 H. W. Henshaw (1875) writes: 



At Camp Grant, Ariz., in tlie latter part of September, this hawk was present 

 in very large numbers. About a mile below the post, out on the plain, tlie 

 stream was bordered by some large cottonwoods ; and these were habitually 

 used as roosting-places by the Turkey Buzzards and Hawks conjointly, as the 

 whitened appearance of the branches and the ground below testified, as well as 

 the fetid odor in their vicinity. Hawks and buzzards appeared to be on terms 

 of the most intimate companionship with each other, and one tree often held 

 seven or eight of either birds. The buzzards seemed if anything rather the 

 shyor of the two, and were generally the first to start, when immediately the 

 whole band would leave their perches, and begin circling in the air, gradually 

 ascending higher and higher till out of danger. Thus they would continue 

 wheeling about till the coast was clear, when all would again resume their 

 perches. 



Winter. — Most of these hawks spend the winter south of the United 

 States, but a few remain in the southern portions of their range in 

 this country. Major Bendire (1892) says: "On the eastern slopes of 

 the Rocky Mountains it winters from about latitude 39° southward, 

 a few remaining in favorable localities still farther north. On the 

 Pacific coast I have observed a few wintering in southeastern Oregon 

 in about latitude 42°, the majority passing southward, and the birds 

 remaining are probably such as breed much farther north, replacing 

 the regular summer residents, which in turn move south on the 

 approach of cold weather." 



DISTEIBUTION 



Range. — North and South America. 



Breeding range. — Swainson's hawk breeds north to Alaska (proba- 

 bly Mount Sischu, Fort Yukon, and latitude 66° 43' N. on the Alaska- 

 Yukon boundary) ; Mackenzie (Onion River and Fort Anderson) ; 

 Saskatchewan (Quill Lake, Touchwood Hills, and Qu'Appelle) ; and 

 Manitoba (Oak Lake, Trcesbank, Aweme, Carberry, Oak Point, and 

 Winnipeg). East to Manitoba (Winnipeg) ; western IMinnesota 

 (Hallock and Browns Valley) ; Iowa (Forest, La Porte City, Grin- 

 nell, and Sigourney) ; rarely Illinois (Philo) ; rarely Missouri 

 (Pierce City) ; Oklahoma (Norman) ; Texas (Henrietta, San Angelo, 

 Rocksprings, and Cotulla) ; and central Mexico (San Diego). South 

 to central Mexico (San Diego) ; Durango (Rio Sestin) ; probably 

 Sonora (Opodepe) ; and possibly Lower California (near Ensenada 

 de Todos Santos). West to possibly Lower California (near Ense- 

 nada de Todos Santos) ; California (San Diego, Capistrano, Santa 

 Monica, Santa Paula, Santa Barbara, Mount Pinos, Buttonwillow, 



83561—37 16 



