74 H. H. COLLINS 



In a later paragraph, he saj^s, '^A.lthough this first plumag is 

 particularly interesting and instructive, affording frequently 

 clues to ancestral relationships, it has not until recently attracted 

 the attention it deserves, even among 'professional' ornithologists." 



Whitman ('04) in his work with pigeons, appears to have re- 

 garded the comparative study of juvenal plumages as highly 

 important in tracing phylogenetic relationships. On the other 

 hand, it is said that closely allied subspecies sometimes differ 

 more at this early stage than at any later period. Apparently 

 there is still much to be learned concerning the real significance 

 of first plumages. 



Though the general features of the change of pelage have been 

 described in many of the mammals, the ornithologists seem to 

 have proceeded somewhat farther in the study of the details of 

 the process. 



Dwight ('00), in a study of the Passerine birds of New York, 

 writes as follows : 



The plan on which a moult proceeds is a perfectly definite one, al- 

 though often much modified and obscured. Old feathers or rows 

 of feathers tend to remain until the newcomers adjacent have matured 

 sufficiently to assume their function, when the old fall out and their 

 places are taken by the new which develop from the same papillae. 



The systematic replacement of areas of feathers shows most obviously 

 in the wings where not only do the remiges fall out one after another 

 in definite sequence and almost synchronously from each wing, but the 

 greater coverts are regularly replaced before the fall of the secondaries 

 beneath them, the lesser coverts before the median and even in the rows 

 of the lesser coverts alternation seems to be attempted. . . . On 

 the body the protective sequence is less obvious, but the moult regularly 

 begins at fairly definite points in the feather tracts radiating from them 

 in such manner that the outer rows of feathers where the tracts are 

 widest and the feathers of their extremities are normally the last to be 

 replaced (pp. 83, 84). 



Furthermore, Dwight found a regular sequence in the de- 

 velopment of the various feather tracts, although in young birds 

 an outbreak of moult in any of the tracts earlier or later was 

 less unusual. 



Although, as a rule, the moult proceeds so gradually and so 

 simultaneously on opposite sides of the body that the power of 



