GULLS. 513 



across Siberia to the Lena. Nesting in colonies in the vicinity of Lake Ladoga, 

 together with the common tern, the female generally lays three or four eggs, 

 which may be distinguished from those of the former by the orange-red, instead of 

 yellow, colour of their yolks. Whereas the species just mentioned is but a very 

 occasional visitor there, the black - headed gull (L. ridibundus) is a common 

 denizen of the British coasts, showing an especial partiality for flat shores during 

 the winter, but in the spring seeking marshes for the purpose of breeding. In this 

 species the head and upper part of the neck are dark brown, and the beak lake-red 

 in the summer-dress; but in the Mediterranean black-headed gull (L. melano- 



BLACK-HEADED GULL ( liat. size). 



cephalus) the head is jet-black, and the beak coral-red, with a dark band in front 

 of the angle ; while the primary quills, in fully adult examples, are white, instead 

 of parti-coloured. In America the group is represented by the laughing gull 

 (L. atricilla), distinguished from the British species by its larger dimensions, and 

 characterised by having the first three outer primaries black, with minute white 

 tips. The largest member of the group is the great black-headed gull (L. ichthy- 

 aetus), ranging eastwards from the Levant to China, and northwards to Mongolia. 

 In length the male may measure as much as 27 inches (against 16 inches in the 

 black-headed gull); and in the breeding-plumage the adult has a jet-black head 

 and upper neck, the beak orange-red, passing into red at the angle of the mandible, 

 VOL, iv. 33 



