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 Pacitie 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 plumage, 
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 
eburnec) 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. 
Ivory-Gull. 
THE SKUAS. 
Family STERCORARIIDA. 
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 (ceca) 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 Yarvell’s 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 
