244 IT. S. NATIONAL MUSEUM BULLETIN 2,17 



that they remain numerous on the Flats until later in spring. Ap- 

 parently the northern part of their migration is as leisurely and as 

 prolonged in Yukon as in Alaska. (A general discussion of migration 

 is to be found in chapter 6. ) 



Fourteen of our Old Crow specimens still possessed much brown 

 color on the head and rump, a color usually lost at breeding time, 

 leaving the white in sharp contrast with the black on wings and back. 

 It was apparent that the edges on the brown feather tips of our 

 specimens were much weakened and about ready to be shed. The 

 change is not one of wear, as it is commonly called, because it occurs 

 at a predetermined position and leaves the edges of the feathers in 

 a sharp new outline quite in contrast with the irregularly worn con- 

 dition of tips of wing and tail feathers often apparent just before 

 the moult. The brown edging of contour feathers is retained for 

 about nine months and until the buntings are near their breeding 

 grounds. 



We could not detect any distinction in size or plumage which would 

 distinguish between snow buntings from Alaska, Yukon, and 

 Mackenzie. In describing the snow buntings of Siberia as P^ n. 

 paUidior, Salomonseh (1947) remarked that a few moulted speci- 

 mens from western Alaska showed the lighter backs by which he 

 distinguished pallidior from nivalis of "Arctic America, perhaps ex- 

 cept Alaska." We did not have enough specimens in fresh plumage 

 to test Salomonsen's suggestion of a distinct Alaskan color character. 



At the U. S. National Museum Bernard Feinstein pointed out that 

 specimens from Alaska had stouter claws than a series of specimens 

 taken during migration at Fort Simpson on Mackenzie Kiver. On 

 the basis of the average difference in stoutness of claws the Old Crow 

 birds go with those from Alaska rather than with those from 

 Mackenzie. 



In the discussion of snow buntings at Anaktuvuk it was mentioned 

 that many occur in winter scattered through central and southern 

 Alaska. They are separated from those wintering in Mackenzie by 

 a mountainous region in Yukon which seems unsuited for wintering 

 buntings and from which none have been reported in winter. That 

 the geographical separation in winter may also isolate the two popu- 

 lations on their breeding grounds is further suggested by the fact 

 that it has been possible to sort Alaskan from Mackenzie buntings 

 on the basis of stoutness of claws. The resemblance in claw stout- 

 ness between Old Crow and Alaskan buntings suggests that both 

 belong to the Alaskan wintering population and that migration 

 passes eastward along the Porcupine at least as far as Old Crow. In 

 summer there is apparently no geographical gap in the extension of 

 breeding snow buntings along the arctic coasts of Alaska, Yukon, 

 and Mackenzie. 



