BLACK-HEADED GULL. 603 



on the greater part of the outer web, white on the inner 

 web, with a blackish margin and tip ; the second and third 

 primaries white on both webs, with the exception of a hair- 

 streak of black on the outer, and dark margins to the inner 

 webs ; tips black, shafts white ; the fourth white on 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 with a rosy 

 tint ; legs and feet like the beak, lake-red. 



The whole length is sixteen inches ; from the front of the 

 wing to the end of the first quill-feather, which is slightly 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 a nearly adult 

 male bird, two years 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 Gardens of the Zoolo- 

 gical 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. In vigorous birds, 

 and in mild climates, the hood is assumed at an early date ; 

 iii ' The Field ' of 23rd January, 1875, is a record of an 

 individual with a dark head observed at Exmouth on the 

 21st of December, and one with an entirely black hood on 

 the llth of January. 



In the winter plumage the adult has no hood ; but the 

 head is streaked with greyish, and there is a dark patch of 

 the same colour before the eye. and behind the auricles. 



The upper figure in the illustration here given is from a 



