BREWSTER'S WARBLER. 77 



winter plumage are already beginninp; to show in the form of small, sprouting 

 pin feathers. There is no trace of the throat- and cheek-patches in this plumage 

 but the color that overspreads the chin, throat, breast, fore abdomen, and flanks 

 is many shades darker than in even Mr. Sage's specimens. The dorsal surface, 

 too, is darker, while the middle line of the posterior part of the abdomen is 

 whiter, — less heavily tinted with yellow. As the chrysopterae are considerably 

 older, the differences in the colors maj' be in part due to the wear of the delicate 

 juvenile feathers or to the exposure of the deeper parts of the feathers as the 

 body of the bird enlarges. Mr. Outram Bangs has pointed out to me that a 

 change in color such as is here assumed, involving a passage from a lighter and 

 yellower to a darker and more ashy hue, really takes place in the juvenile dress 

 of Hehninthophila rubricapilla as the young bird grows. Observations made by 

 Mr. C. J. Maynard, moreover, confirm me in this belief. In his "Warblers of 

 New England," 1901, pp. 77, 80, Mr. Maynard describes the first plumage of 

 H. chrysoptera, at the time of leaving the nest, as "pale golden ashy throughout, 

 lighter on the abdomen. Tips of two rows of wing-coverts, golden, forming two 

 wing-bars." This description was made by Mr. Majmard in the field, while 

 the little birds were perched on the fingers of a friend. Now this description 

 of the color of the earliest stage of the chrysoptera in its juvenile plumage does not 

 well apply to the two older specimens of chrysoptera whose skins I have before 

 me, but fits the Sage specimens pretty well. I am therefore led to believe that 

 the latter are either chrysoptera or leucobronchialis, and not pinus for the reasons 

 stated above. On a priori grounds one would expect the young of these two 

 forms, chrysoptera and leucobronchialis, to be indistinguishable when they leave 

 the nest, since except for the dark throat and ear patches (which do not appear 

 until the first-autumn plumage) the adults of these two forms are alike. 



Thus, through the lack of sufficient observations bearing on the relations of 

 the birds under discussion, and the meagre material in collections to throw light 

 upon the juvenile plumages, one is foiled at every step in this investigation. 

 What is now wanted is for some one to follow up a young brood, the progeny of 

 a pinus and a chrysoptera, until they have assumed the first-winter dress and so 

 revealed their identity. To do this in the field is a long and laborious task and 

 the circumstances may not always be such as ensure success. It were highly 

 to be wished that experiments in breeding pinus with chrysoptera in an aviary 

 would be undertaken in some place like Bronx Park, where facilities for such 

 experiments are furnished. Yet even in that case grave difficulties are bound 

 to present themselves. Unless each species is secured in a region where the 



