BREWSTER’S WARBLER. ik 
winter plumage are already beginning 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 may 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 Helminthophila 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. Maynard 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 
