v LARIDAE 305 
sion in the herbage, are dull brown or greenish, with somewhat 
indistinct umber markings. The food consists chiefly of fish, 
which the smaller Gulls are forced to disgorge, while Kittiwakes and 
the like are themselves occasionally devoured in default of other prey. 
MW. chilensis, spotted with chestnut above, and more rufous below, 
occupies America south of Rio de Janeiro and Callao; the sooty- 
brown JZ. antarctica—the stouter-billed Port Egmont or Sea Hen— 
replacing it from the Falklands to the Australian and New Zealand 
seas, and reaching northwards to the Comoros and Madagascar. In 
the Antarctic Victoria Land occurs a paler form, JZ maccormickt. 
Stercorarius pomatorhinus, the Pomatorhine Skua, breeds on 
the tundras of Siberia and possibly from Greenland to Bering Sea, 
migrating to Britain and as far as South Africa, North Australia, 
and Peru. The plumage is brown, with blacker head and gorget, 
white breast, and acuminate white neck-feathers tipped with yellow. 
The projecting median rectrices with their vertically twisted vanes 
are mentioned above (p. 301). Uniform brown specimens may be 
immature. SS. crepidatus, the Arctic Skua, is smaller, and nests as 
far south as Northern and Western Scotland, but properly occupies 
Arctic and sub-Arctic Europe, Asia, and America; in winter, 
it reaches South Africa, Australia, New Zealand, and Brazil. The 
elongated rectrices are not twisted, but are pointed, while a uni- 
form dark phase—the true S. richardsoni—is common. to both sexes. 
S. parasiticus, Buffon’s Skua, distinguished from the last-named by 
its extremely prolonged rectrices and greyer upper surface, breeds on 
the Scandinavian fells and throughout the Arctic tundras and barren 
grounds, migrating as far south as Gibraltar and lat. 40° N. in 
America. The habits of the members of this genus are similar 
to those of Megalestris, but their quicker flight enables them to 
rob even Terns, and the mewing cry is most peculiar, while the 
egos are intermediate in style between those of Whimbrels and 
Gulls. These small Skuas often destroy Lemmings. 
Sub-fam. 2. Larinae.—Rissa tridactyla, the Kittiwake, breeds 
from the cireumpolar regions southwards to the Kuril Islands, the 
Gulf of St. Lawrence, and North-West, France ; in winter it reaches 
western North America, the Bermudas, the Canaries, the Mediter- 
ranean, and the Caspian. The feet are black, the hind-toe is 
absent or rudimentary. From Larus canus, which it closely 
resembles when flying, it can be distinguished by the absence of 
white spots at the ends of the primaries. The young bird, or 
VOL. IX xX 
