Notes on the Plumage of North American Sparrows 



NINETEENTH PAPER 

 By FRANK M. CHAPMAN 



(See Frontispiece) 



Snow Bunting (Plectrophenax nivalis Figs. 2-5). The plumage changes 

 of the Snow Bunting are most interesting, few birds presenting a more striking 

 illustration of differences in appearance which are due solely to wear, and not to 

 molt of the feathers. 



The nestling is brownish gray, above indistinctly streaked with black in 

 the center of the back; the breast is grayish, the belly soiled white. Even at 

 this age, the sexes may be distinguished by the greater amount of white in 

 the wing of the male; the primaries, as well as the secondaries, having white 

 areas. As yet these feathers in the male are white only on their concealed 

 basal portion; but it may be said here that as the birds grow older the amount 

 of white increases, until in fully mature birds it occupies the basal third of 

 the feathers. 



At the postjuvenal molt, which, in Greenland, begins in the latter half of 

 July, the body feathers are molted, the tail and wing-quills being retained, 



October January March June 



FEATHERS FROM BACK OF SNOW BUNTING, SHOWING SEASONAL CHANGES 

 IN FORM AND COLOR 3 DUE TO WEARING OFF OF TIPS. (Natural size) 

 (From Handbook of Birds of Eastern North America) 



and the bird passes into first winter plumage (Fig. 4). Males and females, 

 immature and adult birds, now look much alike ; but the male differs from the 

 female, as in the juvenal plumage, by having more white in the wing and also 

 by having the feathers of the crown sub-basally white. That is, in the 

 female the crown feathers are black tipped with brown, while in the male 

 these feathers are white with narrow black bases and sufficiently wide brown 

 tips to completely conceal the white which is so conspicuous in breeding 

 plumage (Fig. 2). 



Aside from a little feather-growth about the head, there is no spring molt, 

 and the change from the brown fall plumage (Fig. 4) to the black and white 

 breeding plumage (Fig. 2) is due entirely to a wearing off of the brown tips of 

 the winter plumage. This occurs gradually (Fig. 5), and feathers taken from 



(18) 



