LARUS. GULL. 525 



repeatedly with considerable celerity, and at the same time 

 retirinof backwards. Their food consists of fish, flesh of dead 

 cetacea, and land quadrupeds, young sea-birds, Crustacea, mol- 

 lusca, asterise, Avornis, and larvse. In stormy weather they 

 often leave their ordinary haunts, and proceed inland, to pick 

 up the larvae and worms exposed by the plough, or found in 

 the pastures. In winter they congregate in large flocks at 

 the mouths of rivers, or on the sands. They rest by day 

 either on shore or floating on the Avater, by night on the 

 sands or rocks, or in the fields, either standing on one foot, 

 with retracted neck, or lying down. In the breeding season 

 they generally keep in flocks, nestling on rocks, headlands, or 

 islands. The nests are composed of dried grass, bits of turf, 

 or sea weeds. The eggs, generally three, are large, oval, 

 greyish or greenish-brown, spotted and blotched with brown 

 and grey. The young, at first covered with parti-coloured 

 down, soon leave the nest, especially if molested, and conceal 

 themselves in crevices or behind stones. The bill, iris, and 

 feet, are generally at first dark, and become lighter as the 

 bird advances in age. The plumage, at first mottled with 

 brown or dusky, gradually becomes lighter, the permanent 

 colours not being acquired until they are three years old. The 

 predominant tints are pure white, pale gi-eyish-blue, or deep 

 slate purple, seeming black at a distance. In winter the head 

 and neck are streaked with brown, in summer pure white. 



The genus Larus has various affinities. It passes so 

 directly into Gavia and Rissa, that these groups cannot easily 

 be defined, the whole forming a very natural group, allied 

 on the one hand to the Petrels and Albatrosses, on the other 

 to the Terns and Skimmers. 



