WESTERN PIGEON HAWK 89 



So I stopped the wagon, alighted from it, made a long detour to a 

 point far ahead of the hawk, and hid behind a bank. As my com- 

 panion came along, the hawk behaved as he had before and finally 

 flew past me near enough for me to secure him. 



I cannot find anything to indicate that the food, voice, or other 

 habits of this bird differ materially from those of other pigeon hawks. 



Fall.— Richardson's pigeon hawk migrates southward in fall, 

 mainly east of the Rocky Mountains, through Colorado, New Mexico, 

 and western Texas. Mr. Randall says that it is one of the last of the 

 migrants to leave Alberta; his latest record is December 5, 1922. 



FALCO COLUMBARIUS BENDIREI Swann 

 WESTERN PIGEON HAWK 



HABITS 



This supposed northwestern race of the pigeon hawk is not a very 

 well marked subspecies. It seems to me to be only an intermediate 

 between two of the other races and therefore hardly worthy of recogni- 

 tion in nomenclature. It is said to be slightly paler above than 

 columbarius, which may be due to interbreeding with richardsoni. I 

 am inclined to agree with Harry S. Swarth (1935), who says: "I have 

 examined series of Pigeon Hawks wherever opportunity has offered 

 without being able to substantiate the existence of a western race, 

 bendirei. * * * I am unable to distinguish between eastern and 

 western examples of Falco columbarius in normal plumage, but it may 

 be desirable to recognize a northwestern subspecies on the same 

 grounds as Buteo borcalis calurus, that is, on the basis of a dimorphism 

 that is prevalent over part of the species' range. For this subspecies 

 the name Falco columbarius suckleyi is available, of course; bendirei 

 should be ruled out in any event." 



What little we have available on the habits of pigeon hawks, in the 

 regions supposed to be occupied by this race, indicates no variation 

 from the habits of the species elsewhere. M. P. Skinner tells me that 

 he has seen them in Yellowstone National Park, some of them "quite 

 dark", during every month from April to October; his earliest date is 

 April 15, and his latest October 10. He says that "these hawks are 

 like the sharpshins in preferring the edges of the forests and the open 

 country, dotted with groves, to the heavy forests." 



Nesting. — H. R. Taylor (1888) writes of a nest, containing five eggs, 

 that he found on April 6, 1888: "It was on a steep mountain side, in 

 Santa Clara Co., Cal., on a ledge of a precipitous bluff about thirty-five 

 feet high." The nest "was composed simply of pieces of friable rock." 



Behavior. — Mr. Skinner says, in his notes: "Although most of the 

 pigeon hawks' prey are small birds flushed and chased down, they are 



13751—38 7 



