V ° 1 i906' 111 ] Beebe, Spring Moult of Larus atricilla. 455 



protruding from their sheaths. These are of a uniform dark slate 

 color with conspicuous white tips to all the barbs. 



March 3. — Considerable change is apparent since last week's 

 examination. Sixteen new feathers have appeared on forehead 

 and crown, all with long white tips. The most marked change 

 is about the eyes, where the white encircling feathers and the dark 

 fluffy, down-like ones at the anterior edge have all appeared and 

 grown to almost full size. 



March 10.— Hardly any progress in the moult is noticeable 

 since last week. A number of the winter feathers come out at a 

 touch. The severe cold of the past week may have temporarily 

 retarded the moult. An area three quarters of an inch square, 

 on the crow r n, was cleared of new feathers (three in number) and 

 thirty winter feathers, not much worn and firm in their sockets, 

 were conspicuously marked with indelible ink. 



March 19. — A very noticeable increase in new feathers has taken 

 place, about eighty having pushed out the winter feathers and 

 showing a full eighth of an inch of dark sheaths beyond the papilla?. 

 Fourteen of the thirty marked feathers have been shed. 



The white tips of the score of growing feathers which were ob- 

 served on February 24 have almost disappeared. From careful 

 comparison with other new feathers in various stages of growth, it 

 appears that these white tips remain until the feather has reached 

 its full size, then not singly, but almost en mass, they break off and 

 are lost, never contributing, to any appreciable extent, to the color 

 of the hood. 



During the last two weeks a great deal of wear has taken place 

 among the remaining winter feathers. Those on the crown and 

 occiput (including the ink-marked ones) have lost much in sym- 

 metry of vane and in number of distal barbs. On the chin and 

 throat, a similar condition of wear and tear is apparent to even 

 a much greater extent, only here it is the bases of the feathers 

 which have suffered most, in many cases having become com- 

 pletely denuded of barbs, while the distal half is still perfect. 

 Everywhere is a scattering of new, half-grown feathers, although 

 those which remain of the old plumage seem as firmly fixed as ever. 

 The most careful search fails to reveal one feather, which, at a 

 glance, cannot be instantly classified either as a worn-out winter, 



