64 BREWSTER'S WARBLER. 



If perchance two of these famihes met together in their movements to and 

 fro through the swamp (we saw this happen only twice during our long watches) 

 a momentary confusion would ensue, but this would be quickly dispelled by the 

 segregation of the different family groups. 



The range of these birds extended occasionally into the Gray Birch growth 

 that abutted on two sides of the swamp. It was interesting to find that the 

 open oak wood on the south, barren of any undergrowth, proved to be a barrier 

 to their progress in that direction as effectual as the Bobolink meadow on the east. 



A similar mode of life while rearing their young was followed by the numer- 

 ous Veeries, Chestnut-sided Warblers, Oven-birds, Maryland Yellowthroats, 

 and Indigo-birds, that inhabited the same swamp. The Black-and- White 

 Warblers and Redstarts, on the contrary, took care of their broods up in the trees. 



By the fourth of July the young birds belonging to the oldest brood had 

 acquired in a large degree the first-winter plumage and were approximately as 

 large as their parents. Their color is now gray above, tinged with olive, more 

 . especially on the rump and upper tail-coverts. Lores black, but the black color 

 not easily traced behind the eye. Forehead yellow, as in the adult female 

 leucobronchialis and chrysoptera. Below, dull ash, washed with yellow, including 

 the throat. Wing-bars pale yellow. The breast has a patchy or spotty ap- 

 pearance, evidently caused by the transition from the darker juvenile to the 

 lighter first-winter plumage. 



On the tenth of July we saw at least three of the young of this family, when 

 they appeared to be as large as their parents and were hardly distinguishable 

 from them if it were not for the fact that the old birds were still busily engaged 

 in feeding them, and that the characteristic chirruping of the young was still 

 kept up. In fact the plumage of the young was now brighter than their mother's, 

 their polls being more extensively yellow, their lower parts whiter. The wing- 

 bars which were double and widely separated in the juvenile plumage now seemed 

 to be reduced to a single yellow bar. 



We have now followed up the brood which issued from the nest on the 

 seventeenth of June to a point where they have essentially acquired the plumage 

 of the adult, and we have seen them develop into pure Brewster's Warblers 

 (i. e. in plumage). By keeping them under observation until the completion of 

 the post-juvenal moult it has been demonstrated that they are not only not 

 chrysopteras but not even transitional forms in any respect between chrysoptera 

 and leucobronchialis, but leucobronchiales of extraordinary purity. 



' Probably because one set of coverts had not yet been renewed after the post-juvenal moult. 



