1926] Swarth: Birds and Mammals from the Atlin Region 103 



acquired barred feathers of the neck and upper breast persist until 

 replaced by white ones in the fall. Late in July and early in August 

 the rectrices and remiges are renewed, accompanied usually by the 

 appearance of the first white winter feathers upon the abdomen and 

 flanks. The two white central tail feathers persist, in some cases at 

 least, until the end of the summer, though they are hidden by long 

 upper tail coverts. Whether or not these late retained feathers are 

 at once replaced with other white ones I do not know. 



The above remarks all pertain to the adult male. The adult female 

 undergoes a more or less extensive molt, beginning late in July, follow- 

 ing the barred breeding plumage and marking a M^ell-defined plumage 

 stage. She then acquires, above and below, finely mottled feathers like 

 those of the male, but this plumage is never (or at any rate very 

 rarely) acquired in its entirety before the white winter feathers 

 appear. Young birds of both sexes begin a replacement of juvenal 

 plumage with finely mottled feathers as in the adult, but here, too, the 

 white winter feathers appear before the first change is accomplished. 

 So quickly do the several molts follow one another during the summer 

 months, that it is not uncommon to find female birds in August with 

 remaining patches of white feathers from the previous winter, the 

 greater part of the body clothed in the barred breeding plumage, 

 some extensive areas of mottled feathers of the "winter plumage, 

 preliminary, ' ' and some areas of new white feathers. 



Lagopus leucurus leucurus (Swainson). White-tailed Ptarmigan 



Occurs, apparently not abundantly, at high altitudes. The pre- 

 dilection of this species for exposed, rocky ridges is reflected in the 

 local name "rock ptarmigan. ' ' The few people we met who recognized 

 the existence locally of three species of ptarmigan called the true rock 

 ptarmigan by the name of ' ' croaker. ' ' 



I encountered the white-tailed ptarmigan on but one occasion, on 

 September 1, when a flock of from fifteen to twenty birds was flushed 

 on a rocky slope between the head waters of Spruce and McKee creeks, 

 at about 5000 feet altitude. Three specimens were collected (nos. 

 44725-44727), an adult female and a young male and female. In all 

 three the lower breast and belly are clothed in new white winter 

 plumage, the molt on those parts being direct from the barred breed- 

 ing plumage in the case of the old bird, from the juvenal plumage in 

 the young. Elsewhere these birds are entirely in the soft gray colors 

 of the "winter plumage, preliminary." 



