APPENDIX. 463 



grey winter feathers of head and neck falling oif, and new white ones 

 appearing. In a bird shot so early as the 12tli of this month, in 

 1846, the neck was pure white. 



March 10, 1849. Adult shot to-day, exhibited pure white plumage 

 on head and neck, and other new white feathers were in pens. 



Larus ridibundus. March 16, 1848. — Two of these birds, shot to- 

 day, were brought to me to prove that the white feathers of the 

 head fall off in spring, and are replaced by wholly new black feathers. 

 One bird was perfectly adult, and did show this ; the black feathers 

 being so far advanced beneath the white ones, that when these latter 

 drop off, the head is perfectly clothed in black, which accounts for the 

 sudden transition that takes place. There are many pen feathers through- 

 out the entire neck of this bird, as in that of the herring-gulls exa- 

 mined a few days ago — a circumstance which I note in consequence of 

 the change of colour being confined to the head in the one species, 

 and prevailing throughout the neck in the other. 



April 16, 1850. An adult bird of this species obtained by Dr. 

 J. D. Marshall, last October, retained (as he informs me) its winter 

 plumage on the head (pure white, with the black ear-spot) until the 

 6th of April, when it commenced getting black, and on this day had a 

 perfect black head, having been just ten days in acquiring the change. 



July 14, 1850. I examined Dr. J, D. jVIarshall's living bird, already 

 noticed, and a finer masked gull (L. capistratus), as to form of mask 

 and its pale broccoli-brown colour, could not possibly be. 



Lams canns. March 7, 1849. — An immature bird, having a few 

 feathers only of adult plumage on the back, has the entire feathers of 

 the throat new. 



Larus rissa. February 1849 (end of). — Grey winter feathers of 

 head and neck dropping off in an adidt bird, and new white feathers 

 appearing. 



Alca torda. February 25, 1848. — An adult razorbill, killed at 

 Strangford Lough on the 22nd, was brought to me in the flesh, that I 

 might see the state of plumage of its neck and head. Forehead and 

 top of head (which are black in summer and winter) exhibit both 

 old and new black feathers. Feathers on sides and back of neck either 

 white or black, the white falling out, and young ])lack rising to supply 

 their place : the black are sufficiently grown to completely clothe the 

 bird before the white ones fall out. There is no moult s-oine: on in 



