40 PROCEEDINGS OF THE ACADEMY OF 



Chroecoceplialus atricilla. 



Extremel}' abundant, in spring and fall. They appear the last 

 of March or early in April, and become plentiful during the latter 

 month. They remain so late, and are absent so short a time 

 during the summer, that I think some breed near by, though I 

 found none actually' nesting in the vicinity. Probably onlj' two 

 years, instead of three, as in the ease of the larger Lari, are 

 required for them to assume the perfect plumage. The majority 

 of the spring birds are in full attire, but among them a large 

 number of the conspicuously brown birds of the preceding year 

 are always seen. A few return in August, many more in Septem- 

 ber, and by the last of this month their number defies computation. 

 It is no exaggeration to say that I have seen a thousand rise at 

 the same moment from a single sand-bar where they were resting 

 and Illuming themselves after feeding. They fish in companies 

 often of numbers but little iuferior, following the shoals of small 

 fry about the harbor, continually descending upon them, and 

 rising on wing again after a moment's half-submergence. At 

 such times they are in pursuit of the small fish that form the 

 principal food of the blue-fish, and their presence is an unfailing 

 guide. At this season the brown birds greatly outnumber the 

 others. The adults are mostly moulting when they return, and 

 retain traces of the spring plumage — seen in a slight glow of the 

 under plumage, carmine tint in the duskj^ of the bill, red mouth, 

 and slate about the head — at least until October, when the renewal 

 is completed. The young of the year are quite definitely brown, 

 etc., and bear little resemblance to the parents; but they may 

 always be distinguished from any other gull by the length of the 

 tarsus in comparison Avith the toes, and by the downward curva- 

 ture of the end of the bill, which is sufficient to bring the tip 

 nearly on a level with the angle at the sj'mphysis. The birds thin 



race of "herriug-gulls," as argentatus, occidentalism etc., the same parts 

 are streaked with lighter dusky. lu the gulls without black on the primaries, 

 as glaucus, glaucescens, leucopterus, etc., this winter marking takes the form 

 of obscure cloiidijig with grayish. These distinctions hold good with all 

 the species of the family with which I am acquainted, and, moreover, the 

 darkness of the plumage of the young of the year, in all, is correspondingly 

 graduated from smoky -brown to pale gray. Similarly, the primaries and 

 tail-feathers of the "white-winged" gulls above mentioned are, for the first 

 year, gray like the general plumage ; while those of the others (including 

 marinus) are black. 



[May 2, 



