6 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



adult. Mr. Turner says that subsequent plumage changes are much 

 like "those of the snowy owl and extremely old birds become pure 

 white with the exception of the tips of the wings." 



Food.- — The two species of ptarmigans seem to furnish the principal 

 food supply of this gyrfalcon, especially in winter, when they are 

 about the only birds available in the far north. Mr. Turner says 

 that at Fort Chimo it is called the "partridge hawk" by the English- 

 speaking people, who apply the name of "partridge" to both ptarmi- 

 gans and to the spruce grouse. Manniche (1910) says that it feeds 

 mainly on lemmings in northeastern Greenland, as well as on various 

 birds and occasionally on the Alpine hare. When springtime brings 

 the hosts of summer birds to the Arctic shores, the falcons feast and 

 feed their young on the numerous sea birds, dovekies, puffins, murres, 

 guillemots, and kittiwakes. They are even strong enough to kill 

 the eiders and other ducks and geese. The smaller land birds and 

 shorebirds arc less often taken, but golden and ringed plovers, phala- 

 ropes, snipes, turnstones, dunlins, purple sandpipers, and snow bunt- 

 ings have been recorded in their food. 



Manniche (1910) writes: 



The falcons appeared most numerously near the ship to which they were 

 allured by the pigeons of the expedition. From September 3rd to 17th 17 falcons 

 were shot here. Often 4 to 5 individuals would appear at one time either circling 

 around the mast-heads, on which they sometimes settled, or sitting around on the 

 surrounding hummocks of ice or blocks of stone, watching for pigeons. 



As soon as these were started in the air, they were most violently pursued by 

 one or several falcons which, however, never succeeded in capturing a pigeon. 



I often saw a falcon and a pigeon manoeuvering for a long while extremely high 

 up in the air until the pigeon finally — swift as an arrow — vertically shot down to 

 the ship and entered the pigeon-house, which was built on the deck, all the while 

 pursued by the falcon, which stretching its talons forward and uttering angry 

 cries would only give up the chase just before the entrance-hole of the pigeon- 

 house. During this autumn 40 falcons were shot — all of them young birds, and 

 at least 5 times as many were seen. 



During its winter wanderings this falcon preys on the native grouse, 

 and sometimes attacks domestic poultry. Elsie Cassells (1922) re- 

 ports that "a fine specimen of the White Gyrfalcon was shot by Mr. 

 Waghorn on his farm at Blackfalds, Alberta, in the act of attacking 

 one of his turkeys in December, 1920." M. J. Magee (1932) refers 

 to two cases of its eating prairie chickens; in one case "the bird had 

 inside it 140 grams of Prairie Chicken, meat, bones and feathers." 



Behavior. — There seems to be no great admiration among observers 

 for the swiftness and skill of the gyrfalcon in capturing its prey in 

 flight. The foregoing statement by Manniche (1910) would seem 

 to indicate that the pigeons were more than a match for it. Hagerup 

 (1891) had a similar experience; he flew his pigeons regularly to attract 

 gyrfalcons but never lost a pigeon. Manniche (1910) also says that 

 a gyrfalcon cannot catch a phalarope on the wing. Kumlien (1879) 



