574 LARIDJE. 



the outer web, grey on the inner web, and edged with 

 black ; the fifth and sixth grey on both webs, the edge of 

 the inner or broader web and the point black ; tail-coverts 

 and tail-feathers white ; front of the neck, the breast, and 

 all the under surface of the body and tail, pure white ; legs 

 and feet like the beak, vermilion red. 



The whole length is sixteen inches ; from the front of 

 the wing to the end of the first quill -feather, which is the 

 longest, twelve inches. Bewick's figure of the Black- 

 headed Gull represents a bird in this state of plumage ; 

 the lower figure in the illustration here given is from an 

 adult male bird, one year old, killed at the nest in the 

 breeding-season, but still exhibiting some slight traces of 

 immature colours in the few brown feathers on the anterior 

 part of the wing, and in the narrow black tips to the tail- 

 feathers. 



The assumption of the dark colour on the head in the 

 spring is very rapid. A Gull in the collection at the Gar- 

 dens of the Zoological Society, began, some years since, to 

 change colour on the head, from white to dark brown, on 

 the llth of March; it was a change of colour, and not 

 an act of moulting, no feather was shed, and the change 

 was completed in five days. Another bird, some seasons 

 afterwards, had not completed the dark colour till the 

 beginning of May, but the time required for the change 

 was not noted. 



The upper figure in the illustration here given is from a 

 young bird of the year killed in August ; at which period 

 the head is marked with greyish-brown, on a ground of 

 white ; the back, scapulars, smaller wing-coverts, and the 

 tertials mottled with brown; greater coverts and secon- 

 daries French grey ; primaries as in the adult bird ; tail- 

 feathers white, with a broad bar of black at the end; 

 beak, legs, and feet, yellowish -brown. 



