FALCONS, CARACARAS, ETC. 303 



gether unpleasant, resembling somewhat that of Sea Gulls, but near- 

 by it is grating and suggests a maniacal laugh." Dr. William L. Ralph 

 writes in Bendire's 'Life Histories': "The cry of the male is a loud and 

 clear cac-cac-cac, quite different from that of the female so much so 

 that I could always recognize the sex of the bird by it; the call of the 

 latter is more harsh and often broken." 



The conspicuous white head and tail of adults of this species render 

 it easy of identification even at a considerable distance. Young birds 

 too closely resemble Golden Eagles to be distinguished with certainty, 

 but the rarity of that species in the east makes it probable that any 

 Eagle observed is a Bald Eagle. 



36. FAMILY FALCONID^E. THE FALCONS, CARACARAS, ETC. 



It is resemblance in structure rather than in habit which places the 

 members of the genera Falco and Polyborus in the same family. In the 

 former, predatory bird-life reaches its highest development; in the latter, 

 we have birds not distantly removed from Vultures in the character of 

 their food. From the great Arctic Gyrfalcons, nearly two feet in length, 

 to the Indian Pygmy Falcon, no longer than a Song Sparrow, the Falcons 

 are keen winged, dashing, fearless hunters among birds. They have not 

 the soaring habits of the Buteos, from which they may be distinguished 

 by their more pointed wings and more rapid wing-stroke. Their nests 

 are less bulky than those of our buteonine Hawks, the eggs in some 

 species being laid on the bare rock or in a hollow tree. (For Key see 

 antea under Buteonidce.) 



353. Falco islandus Brunn. WHITE GYRFALCON. Legs, and usually 

 under tail-coverts, always white, unmarked. Ads. Head white, finely 

 streaked with black; scapulars, interscapulars, and wing-coverts white 

 with broad bars or semi-lunes, rarely guttate spots of slaty fuscous; tail 

 sometimes wholly white, usually broadly or narrowly barred with slaty 

 fuscous; underparts white, with sometimes a few small grayish spots or 

 streaks. Im. Similar, but upperparts brownish gray with white margins 

 and broken bars; tail barred with brownish gray; underparts more heavily, 

 sometimes uniformly streaked. L., 22'00; W., 16'00; T., lO'OO; B. from N., 

 95. 



Remarks. The white, unmarked under tail-coverts and prevailing white 

 color will distinguish this bird from any form or phase of Falco rusticolus. 



Binge. Arctic regions. Resident in Greenland; in winter casual s. 

 to Ort., N. S., and Maine. 



Nest, on rocky cliffs. Eggs, 3-4, varying from creamy white, spotted or 

 blotched with cinnamon-brown, to uniform pale reddish brown, spotted 

 or blotched with shades of the same color, 2'30 x 1*85. Date, Umanak, 

 Greenland, May 26 (Thayer Coll.). 



"The food consists of waterfowl and other birds largely of vari- 

 ous arctic species of Grouse which are captured on the wing. All these 

 northern Falcons were formerly esteemed for hawking, as they still 

 are by the Mongol races; their style of flight is magnificent much 

 swifter than that of the Peregrine and both are deadly 'footers' 

 (i. e., tenacious of grip), but they lack spirit and dash" (Saunders). 



