404 BRITISH BIRDS. 



as mice, voles, and shrews, also form part of their bill of fare 

 when driven by stress of weather inland. 



The Black-headed Gvll {L. rirdilmndus). — This gull is very 

 diflferent in plumage in summer and winter. In summer the 

 head and neck of both male and female are dark-brown ; in 

 winter this coloration has quite gone, those parts being pure 

 white. In spring the brown colour again appears. This change 

 is not due to a fresh moult, but to an actual change of colour in 

 the existing feathers. The legs and bill are bright red. The 

 young birds have quite a different plumage, being much darker, 

 the dark -brown feathers being mottled at their edges with 

 yellow, and the feet yellow, not red. This gull breeds inland on 

 marshes and flats as well as along the coast, and it is especially 

 during the breeding season that they destroy so many noxious 

 insects. The nest is made by trampling down a number of 

 reeds, grass, and sedges ; in this concavity during April and 

 May three dusky-olive eggs spotted with black are laid. 



The Heii-ing Gull (L. argentatus). — This gull is one of our 

 largest species, often reaching two feet in length. The head 

 and neck are white, often in summer with brown streaks ; the 

 wings and the back are pale bluish-grey, the primary feathers 

 being black and grey with black shafts and white tips, and the 

 secondary feathers also edged with white. The bill is yellow 

 and the feet light pink. The herring gull builds its nest on 

 steep cliffs and rocks, in which are deposited three olive-brown 

 eggs spotted with dark brown. This gull is one of the com- 

 monest that we see following the plough in the south of 

 England, and seems especially fond of the large soft chafer 

 larvEB. 



The only other gull seen abundantly in our fields is — 



The Ciimincjn Gull (L. irmuti). — The common gull justly 

 deserves its name, for it may ho found all round our seaboard 

 and often abundantly inland. It is not so big as the herring 

 gull, seldom attaining a greater length than eighteen inches. 

 The head and nock arc white with dusky spots, ventral surface 



