302 CHARADRITFORMES CHAP. 
Bonaparte’s Gull. All walk well, though sedately, swim to per- 
fection, and rise easily both from land and water, usually break- 
ing into a run before taking to the wing from the ground ; while 
they almost invariably alight with uplifted pinions. The wild 
characteristic note varies less than in most large groups, that of 
the bigger species being harsh and querulous, that of the smaller 
“laughing” or screaming; the lesser Skuas give vent to a 
curious mewing cry, and the Great Skuas to a similar but deeper 
sound. At the breeding-quarters the utterances are naturally 
more agitated and shrill, and the parents hang excitedly above 
a visitor’s head. The food consists mainly of fish, molluscs, 
crustaceans, and worms, but is varied in the stronger forms by 
small mammals, young birds, and eggs: the Great Black-backed 
Gull undoubtedly attacks lambs and weakly ewes; carrion is 
not uncommonly devoured; and Larus maculipennis acts as a 
scavenger at Buenos Aires, besides clearing the country of grass- 
hoppers, and robbing the Cayenne Lapwing of its insect booty. 
Skuas give chase to their smaller kin, and force them to disgorge 
the fishes they have just caught, while even Solan Geese are 
sometimes victimized ; Larus scopulinus, moreover, which robs the 
Oyster-catcher of New Zealand, is a further instance of parasitic 
habits. Insects and their larvae, turnips, berries, and grain are 
also eaten by these omnivorous but useful creatures. Their main 
sustenance is naturally derived from the ocean, or its oozy shores ; 
but flocks are commonly seen on pastures and arable lands near 
the beach, or following the plough further from the sea, though 
not being of the species which breed in the interior, nor 
driven inland by stress of weather. At times Gulls almost, if 
not quite, disappear below the water when swooping on their 
prey, and Kittiwakes have been said to pursue it beneath the 
surface. A common habit is that of preening and washing the 
plumage in company at favoured spots, while one that is less well- 
known is that of casting up the indigestible parts of the food in 
pellets, as do many other birds. The nesting sites are very 
frequently precipitous rocks and stony islands, but inland 
marshes and lakes accommodate many species, while in certain 
localities trees as high as thirty feet are selected. Skuas breed 
on moors or hills near the sea in Scotland, on the fells of Scandi- 
havia, and on the tundras and barren grounds of the Arctic Regions, 
the nest being a mere depression in the herbage or moss; the 
