438 LARID.E. 



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 

 cxhibitinof some slidit traces of immature colours in the few 

 brown feathers on the anterior part of the Aving, 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 

 1 1 th 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 Avas 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 secondaries 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. 



BewicFs figure of the Red-legged Gull is from a bird in 

 the plumage of its first Avinter, as indicated by the markings 

 on the anterior part of the wing, and the narrow black bar at 

 the end of the tail. In the truly adult bird in winter the 

 head is but slightly marked with a dusky patch at the ear- 

 coverts ; the back and wings uniform French grey ; the 

 Aving-primaries as already described ; tail-coverts and tail- 

 feathers pure Avhite ; neck, breast, and all the under surface 

 of the body, also pure white ; bill, legs, and feet red. 



