ASIATIC GYRFALCON 17 



detail. In general appearance this race is somewhat lighter and less 

 gray above than rusticolus, much lighter and somewhat grayer than 

 obsoletus, but decidedly darker than candicans. The wing formula 

 given by the describers, fourth primary longer than first, seems to be 

 very variable and unreliable as a subspecific character. 



The Deering bird, referred to above, is in fresh juvenal plumage. 

 The crown and nape are buffy white, streaked with "clove brown", 

 and much whiter than the back ; in obsoletus the crown is uniform in 

 color with the back, or even darker; the rest of the upper parts is 

 "clove brown", edged on the mantle and lesser wing coverts, and 

 spotted, notched, or partially barred on the greater coverts and 

 scapulars with pinkish, or buffy, white; there are broken bars of the 

 same on the tail; the under parts are white, tinged with buff, with 

 broad, elongated spots or streaks of "clove brown"; the inner webs 

 of the primaries are deeply notched or barred with "light pinkish 

 cinnamon" to white. In older immature birds the edgings have worn 

 away and the buffy tints have faded out to white. At this stage the 

 young are much like young birds from Iceland. 



In fully adult plumage the crown is white to "pale pinkish buff", 

 heavily streaked, especially posteriorly, with blackish brown; the 

 mantle, scapulars, and wing coverts are "olive-brown" to "clove 

 brown", more or less heavily, transversely barred with white, buffy 

 white, or grayish white (not gray, as in European birds); the lower 

 back, rump, and upper tail coverts are broadly banded with dark 

 and light shades of "neutral gray"; the tail is broadly banded with 

 "hair brown", or "fuscous", and gray mixed with white; the under 

 parts are white, the throat and fore-breast pure white, except for 

 a few narrow to almost invisible dusky shaft-streaks; the belly is 

 spotted and the flanks are barred with sepia or blackish brown; the 

 under tail coverts are barred with the same. Except for whiter 

 heads and more white, less gray, in the barring on the mantles, these 

 birds now look very much like adults from Europe. 



Food. — According to Mr. Bull, the food of the Asiatic gyrfalcon, 

 in the Goodnews Bay region, includes the local subspecies of both 

 the willow and the rock ptarmigan, as well as lemmings, snowshoe 

 rabbits, minks, and weasels. 



Behavior. — J. A. Munro (1936) gives the following account of the 

 behavior of one of these falcons that he observed in British Columbia, 

 on December 19, 1935: 



I was motoring past a small brush-fringed creek in otherwise open country 

 when someone shot at, and missed, a female mallard which then flew over the 

 open range toward Okanagan Lake. A large falcon suddenly appeared and 

 flying after the duck on the same level gained upon it rapidly, whereupon the 

 duck swerved from its former straight course and the falcon shot past it. The 

 duck then spiraled down to a small ice-covered pond where it alighted. The 

 falcon flew swiftly toward the standing bird and in the next five minutes or so 



