SKUAS. 



517 



Behring Sea this condition is much more common. Measuring 15 inches in length, 

 the kittiwake, in the summer-plumage of the adult, has the upper-parts white and 

 grey, the tail white, the first to the fifth primaries tipped with black, the under- 

 parts white, the beak yellow, and the legs brownish black. The kittiwake is a 

 resident in the British Isles, where it breeds in numbers on rocky cliffs, and feeds 

 chiefly on surface-swimming fry of fishes and marine invertebrates. The nests, 

 which are usually placed close together on narrow ledges of rock, are built of sea- 

 weed, and generally contain three eggs. The Pacific species, which exhibits a 

 similar variation with regard to the first toe, may be distinguished by its orange- 

 red legs. 



Conspicuous on account of its uniform delicate white plumaere, 



Ivory-Gull. . . » . . r & > 



faintly suffused with a rosy tint, in marked contrast to which stand 



out the jet black legs and greenish yellow beak, the lovely ivory-gull (Pagophila 



eburnea) alone represents a genus characterised by the shortness of the beak, the 



long and slightly graduated tail, and the connection of the first toe (of which the 



claw is unusually long) with the metatarsus by means of a distinct web. A cir- 



cumpolar inhabitant of the Arctic seas, this gull wanders into temperate regions 



during the winter ; its breeding-places being in Spitzbergen and other regions in 



the far north. In contrast to the snowy white of the adult, the young of the 



ivory-gull are conspicuously spotted with black. 



The Skuas. 



Family StercorariiDj^. 



Closely allied to the gulls, the skuas are considered by Mr. Saunders to form a 

 family by themselves, although many ornithologists are not disposed to admit the 

 necessity for such separation. As a family these birds are characterised by the 

 following features. The beak has a cere at the base, and the tip of the upper 

 mandible hooked ; the breast-bone has but a single notch on each side ; the blind 

 appendages {ccaca) of the intestine are larger than in the preceding family ; and 

 the completely webbed toes are furnished with strong, sharp, hooked claws. 

 Represented by six species, the skuas are all included in a single genus ; and while 

 four of them breed only in the colder regions of the Northern Hemisphere, there are 

 two southern species, one of which {Stercorarius chilensis) is found on the western 

 coast of South America as far as the Straits of Magellan, and thence northwards to 

 Rio de Janeiro, the other ranging from Tierra del Fuego to the Cape, NeW Zealand, 

 and the Indian Ocean. In the last edition of YarrelVs Birds it is stated that 

 " the skuas may be considered as forming a conspicuous portion of the predaceous 

 division among the swimming-birds, as indicated by their powerful and hooked 

 beak and claws. Their food is fish, but they devour also the smaller water-birds 

 and their eggs, the flesh of whales, as well as other carrion, and are observed to 

 tear their prey in pieces, while holding it under their crooked talons. They rarely 

 take the trouble to fish for themselves, but, watching the smaller gulls and 

 terns while thus employed, they no sooner observe one to have been successful 

 than they immediately give chase, pursuing it with fury; and having obliged 



