108 DWIGHT 



any in texture from that of the adult and in a number of 

 species adults and young cannot be told apart, except by osteo- 

 logical characters. This plumage is acquired within about three 

 weeks after leaving the nest in some species, the first signs ap- 

 pearing as V-shaped patches on the breast. In other species 

 which have a complete postjuvenal moult the process of acquisi- 

 tion takes longer and does not begin for a considerable period after 

 leaving the nest. Among the Passerine species of New York, 

 at least, this plumage is fully .assumed before the young birds 

 migrate, except among the Swallows, the Flycatchers and, per- 

 haps, a few others. Sometimes one may see a feather of the 

 Juvenal plumage borne at the apex of a feather of this dress, 

 and, rarely, even a filament of natal down will be found adhering 

 in turn to the ju venal feather. To what extent new feather 

 papillae develop and where is of interest in all early stages, and 

 the subject is perhaps not exhausted. The feathering in the 

 first winter plumage is dense, a dozen layers or more covering 

 the breast for instance, and the colors are usually bright 

 and much " v^eiled " by the overlapping of the long feather 

 tips, the barbs of which are almost always terminally of a paler 

 or different color, the most frequent edgings being buff. The 

 amount of this edging or tipping varies greatly and there is ap- 

 parently always more of it in young birds than in adults of the 

 second or third winters. It readily wears away and in some 

 species striking changes are produced without moult by the 

 time the breeding season arrives. Not only are the concealed 

 colors brought out by the loss of the overlying feather tips, but 

 the shapes of the feathers themselves are changed. This may 

 be called a color change without moult, but there is a sharp di- 

 viding line between this result of wear and the alleged color 

 change ascribed to some sort of unknown cell activity within 

 the feather itself. 



The first winter plumage is completely donned in some 

 species in the vicinity of New York city, as early as the first of 

 August, in others not before the middle of November, while 

 the departed Swallows and Flycatchers are sometimes even 

 later. It may be worn a full year without any moult occurring 



