8 PLUMAGE OF WARBLERS 



Plumages and Moults of the Passerine Birds of New York.') While 

 the bird is in the nest this downy plumage is succeeded by a second 

 plumage which has been termed both the 'first' and the 'juvenal' 

 plumage but which, in my opinion, among altricial birds, may best be 

 known as the nestling plumage. 



Where, in the newly hatched bird, there was down, it is forced 

 outward by the rapidly growing feathers of the nestling plumage, 

 on the tips of which it remains for a brief period. Where there 

 was no natal down, the nestling plumage is the first plumage to appear. 



When, at the age of about twelve to fourteen days, the young 

 bird leaves the nest, the nestling plumage of its body is virtually 

 complete, but the tail is stumpy and the wings, although they support 

 the bird in its first uncertain flight, are not fully grown. Both 

 wings and tail, however, belong also, as we shall see, to the first 

 fall plumage, and the distinctive nestling plumage may therefore 

 be said to be wholly acquired in the nest. 



No time intervenes between the completion of the nestling plu- 

 mage and the appearance of the first feathers of the first fall plumage, 

 traces of which indeed may often be detected in the feather tracts 

 of the breast before the wings and tail are fully grown. 



This first fall plumage is acquired by molt of the feathers of the 

 nestling plumage and the development of a new growth of feathers. 

 The wing and the tail quills and the primary wing-coverts are retained, 

 but the remaining wing-coverts and all the feathers of the body are 

 shed. 



Although there may be some feather-growth during the winter, 

 the first fall plumage remains virtually unchanged until the following 

 spring, when, by a molt involving the feathers of various parts of 

 the body, but not those of the wings and tail, the first breeding plu- 

 mage is acquired. 



With the exception of Helminthophila bachmani, Peucedramus 

 olivaceus, Dendroica chrysoparia, and Setophaga ruticilla, which 

 apparently do not secure their mature plumage until their first post- 

 breeding molt (at the beginning of their second autumn), the first 

 breeding plumage resembles that of the mature bird, except for such 

 minor differences as may be shown in the intensity of color of the 

 wings and tail. 



Following the nesting season, in accordance with the almost 

 universal law of molt, an entirely new set of feathers, including wing 

 and tail quills, is gained, and this, like the plumage of the first fall, 



