STERCORARIID.E— THE SKUAS AND JAEGERS. 211 



Family STERCORARIIDiE — The Skuas and Jaegers. 



Chaeactees. Covering of the maxilla, not entire as in the Larida, the basal half being 

 furnished with a saddle-like horny cere, the lower edge of which overhangs the nostrils; 

 toes fully webbed, the claws strongly curved and sharp ; posterior side of tarsus roughened ; 

 tail more or less graduated, the middle pair of feathers projecting more or less beyond the 

 rest. 



The Family Stercorm^iidm is separated from the Lwidcz chiefly 

 on account of the peculiar bill, which shows a not distant re- 

 semblance to that of some raptorial birds. The species are all 

 predatory in their nature, being, in fact the most predaceous of 

 sea-fowl— veritable "robbers of the sea." The smaller Jaegers 

 (genus St&rcorwrius) pirate upon gulls and other sea-fowl, thus 

 earning the common names of "gull chaser," "jaeger" (hunter), 

 etc.; while the larger skuas (genus Megalestris) , also beat along 

 the shores or even over the land, and besides forcing gulls and 

 other birds to disgorge or relinquish their food, prey on various 

 birds much in the manner of hawks and falcons. Indeed, it is 

 said that at Kerguelen Island, in the Antarctic Ocean, the .'/ - 

 ale8tris cmtwrcticw keeps strictly to the land, where it is very de- 

 structive to ducks and other water-fowl. 



Only two genera are recognized, their characters being as fol- 

 lows : 



1. Megalestris. Size large tin bulk equal to the largest gulls), and form robust; depth of 



bill at base equal to not loss than half of the length <>f the upper mandible, measured 

 along the side; tarsus shorter than middle toe with claw; tail short nearly even, the 

 middle pair of feathers a ■arcely projecting beyond the real ; color dull brownish,- 

 times streaked (never barredlwith paler, the baseof the primaries with a whitish 

 patch, 



2. Stercorarius. Size medium or inther small (noi exceeding the medium-sized gulls), and 



form more slender and graceful; depth of bill at base less than half the length of the 

 upper mandible, measured along the aide; tarsus decidedly longer than middli 

 witholaw; middle reotrloes in the adult projecting far beyond ther< plain 



■ or dusky, often rarled with white or yellowish, in the adult; dusky barred 

 i' iler in young; no white at base "i primai 



