388 STATATORES. 



black tips, and a white spot on each of four or five exterior 

 ones near the ends. All the rest of the plumage is white, 

 and there is no difference between that of the male and the 

 female. The young of the first year have the bill dark horn 

 colour ; the irides and feet dusky ; the general plumage of the 

 body mottled with dull white and brown. The quills dusky, 

 without any black or any white spot at the tips ; and the 

 tail dull white, with a dusky bar at the end, which is rather 

 more rounded than in the mature birds. This plumage lasts 

 for a year with little alteration. At the. moult in the second 

 autumn, or when the birds are about fifteen months old, the 

 feet acquire a reddish blush, the bill and irides become 

 yellowish, the white on the plumage a little purer, and the 

 dark mottling more inclining to ash colour ; the bar on the 

 tail feathers becomes less entire, and partially streaked with 

 white. In the third autumn, the entire white and ash colour, 

 the black on the ends of the quills, and the round spots near 

 the tips, are acquired, and the bill, irides, and feet, become of 

 the colours already mentioned as those of the mature bird ; 

 after which, the birds undergo no farther change. There are 

 also some slight changes in the first and second spring, but 

 they are trifling, compared with those that take place in the 

 autumn. As the changes in the plumage are the conse- 

 quences, not the causes, of maturity in the birds, and the 

 physiological change must take place in the more sentient 

 part of the system, before it affects the feathers, it agrees 

 with all the analogies of nature as well as with the facts, in 

 so far as they have been observed, that these birds, and 

 indeed all birds which are a year or two before they acquire 

 their permanent plumage, breed before that is acquired. The 

 herring-gulls, both in their first and their second plumages, 

 assemble on the breeding grounds in the season, indiscrimi- 

 nately with those on which the plumage is mature ; and as 

 the assembling is part of the same law or instinct with the 



