184 U. S. NATIONAL MUSEUM BULLETIN 217 



apparent that predation upon tliem lias not been sufficient to destroy 

 that community of several hundred swallows, as would surely result 

 if the peregrines obtained from them as much as a tenth of the sub- 

 sistence needed during their Arctic residence, for it would take 100 

 swallows to weigh 3000 grams and provide enough to feed two adult 

 peregrines for about one out of the approximately ten weeks during 

 which they and the swallows are neighbors. 



Perhaps the exertion for capturing a 80-gram swallow, about ^o^h 

 of a peregrine's daily food, is not worth the effort when a peregrine 

 can take a duck equivalent to 30 swallows as easily as a human can 

 remove an apple from his refrigerator. Wliatever condition guides 

 the habits of peregrines it must permit the existence of a neighboring 

 population of cliff swallows. 



Falco columbarius Linnaeus 



The first pigeon hawk was reported seen on April 30. The swiftness 

 of its flight left identification uncertain, but this early date did not 

 surprise us, for a pigeon hawk was seen harrying jays in mid-March 

 on the Alatna Malemute, just south of tree line in the central Brooks 

 Kange, and Dall (Dall and Bannister, 1869) found them in winter 

 at Nulato. Another pigeon hawk was reported at Old Crow on May 8, 

 but these small falcons are difficult to identify by sight because of the 

 swiftness of their flight when close to brush and timber. Pigeon 

 hawks have been reported on the lower Porcupine (Williams, 1925) , 

 at Lapierre House (Eoss, 1862), and on the upper Sheenjek River 

 (Kessel, Murie, and Schaller, Unpubl. Ms.) . 



The Indian name is Chin tettree. 



Family TETRAONIDAE: Grouse and Ptarmigan 



Sharp-tailed grouse {Pediocetes) were known by several Indians 

 who had seen them along the Yukon River, where they were called 

 "willow" grouse, a name also used in Alaska. They said that there 

 were none near Old Crow. No information was obtained concerning 

 white-tailed ptarmigan, but they have been recorded at Lapierre House 

 (Ross, 1862). 



The numbers of willow ptarmigan near Old Crow were locally re- 

 garded as showing a great decline in 1957 from their usual abundance. 

 Varying hares were also few. We did not hear of a living hare being 

 seen in spring of 1957 and ourselves saw only three fragments which 

 appeared to be relics from winter, but the tracks of hares were not 

 unusual and some were fresh. Periodic decreases of willow ptarmigan 

 and hare are known locally to occur, but we did not inquire about the 

 relation of their cycles. 



