114 EGGS OF BRITISH BIRDS. 



boldly marked than others, the spots being often confluent and 

 forming an irregular zone round the larger end. They vary in 

 length from 2'85 to 2'5 inches, and in breadth from 1'93 to 1*8 

 inch. It is impossible to distinguish the eggs of the Iceland Gull 

 from those of the Lesser Black-backed Gull and the Siberian 

 Herring-Gull (L. a/finis). Eggs of the Common Herring-Gull 

 resemble them closety, but are, on an average, slightly larger and 

 richer in colour. 



THE KITTIWA K E. 

 (Larus tridactylus.y 



Plate 32, Figs. 1, 2. 



The Kittiwake is one of the most abundant of the British Gulls, 

 but as it is exclusively a rock bird, its colonies are confined to 

 certain districts. It is a circumpolar bird, breeding on the coasts 

 of the Arctic Ocean, and on Iceland, the Faroes, Spitsbergen, and 

 Novaya Zemlya. In the Atlantic its breeding range extends along 

 the coast of Norway as far south as lat. 62°, south of which there 

 appears to be no breeding stations except those on the British 

 Islands and on the rocky coasts of Brittany. In Asia it breeds as 

 far south as the Kurile Islands, and on the west coast of the Pacific 

 as far south as the Aleutian Islands. On the west coast of the 

 Atlantic it is not known to breed further south than Labrador. 



The Kittiwake's nest is better made than is usual with the 

 Gulls. In some districts the foundation is made of turf, with the 

 soil adhering, which the salt spray and wet feet of the birds soon 

 turn into a kind of mortar. This foundation is finished off into a 

 nest made of seaweed, pieces of marine vegetation, and finally 

 lined with dry grass and sometimes a few feathers. 



The eggs are two or three in number, but in some cases four 

 are laid ; they vary in ground-colour from pale greenish-blue and 

 olive-brown to pale buff and buffi sh-brown, spotted and blotched 

 with rich reddish-brown and with underlying markings of pale 

 brown and grey. On some eggs the spots are small and evenly 

 distributed over the whole surface, but on others the blotches are 

 large and confluent, and form an irregular zone round the large 



* Rissa tridactyla — Saunders, Manual, p. G67. 



