58 BRITISH BIRDS 



Eggs. Usually 2-3. Much like those of the two preceding 

 species, but more boldly marked and larger. Av. size, 

 3 x 2* 13 in. Laying begins April May. One brood usual. 



114. GlailCOUS-gull [Larus glaucus Briinnich]. Winter 

 visitor, chiefly to our north and east coasts. Occurs in 

 summer, but not to breed. 



Bird. Length 29 in., therefore about the same size as the 

 preceding species, from which it may be distinguished in adult 

 plumage by the entire absence of black. Mantle and wings 

 mostly pearl-grey ; rest of plumage white. Legs pink. Beak 

 yellow with patch of orange on the angle of the lower 

 mandible. Size apart, No. 114 applies also to the rarer Iceland- 

 gull (22 in.), which is also a winter visitor. 



The young is mottled greyish-buff, which grows paler until 

 the plumage becomes wholly white in the fourth year, to be 

 followed by the grey and white of the adult stage. 



115. Kittiwake [Rissa tridactyla tridactyla (Linnaeus)]. 

 Resident and widely distributed. Strictly marine. 



Bird. Length 16 in. Same size as the blackheaded-gull, 

 but distinguished both from it and the common-gull by the 

 vestigial hind-toe usually a warty excrescence with a small 

 claw by the black or dark grey legs, and, in flight, by the 

 conspicuous black triangular tip to the wings ; also by its 

 note, Kitti-way-ek, which gives it its name. Mantle and wings 

 mostly bluish-grey, rest of plumage white. Beak greenish- 

 yellow, black in the fledgling, and the inside of the mouth a 

 gorgeous orange-red, yellow in the fledgling. Fledgling and 

 immature birds have a more or less complete dark collar, a 

 greyish-black band on the wings and dark rim to the tail, but 

 resemble the adults in the general white-grey of the plumage, 

 thus differing conspicuously from other young gulls. 



Nest. Place : on ledges of cliff faces or walls of sea-caves. 

 Material : sea-weed, grass, moss, earth. Usually a solid 

 structure. Species nests in colonies, often with razorbills, 

 guillemots, puffins, and gannets. 



Eggs. 2-3. Greyish-white to olive-buff, spotted and 

 blotched with dark brown and ash-grey. Av. size, 2-21 x 1*6 

 in. Laying begins end May to early June. One brood. 



(3) Family: Laridce. (c) Subfamily: Stercorariince Skuas 



116. Great-skua, bonxie, skooi [Megalestris skua (Briin- 

 nich); Megalestris catarrhactes (Linnaeus)]. Breeds in Shet- 

 land. Elsewhere winter visitor to our coasts. 



Bird. Length 21 in. Recognised by the hooked upper 

 mandible and bluish cere, the general umber-brown of the 

 plumage, and the large white patch across the dark brown 



