ORDER LONGIPENNES. 



LONG-WINGED SWIMMERS. 



Family STERCORARIID^. Skuas 

 and Jsegers. 



jEcger (adult). 

 (Immature birds lack the long middle tail feathers.) 



The Jaegers are pelagic species, although they occasionally occur 

 on the Great Inland Lakes. They feed principally upon fish, much 

 of which they obtain by chasing and robbing the gulls and terns of 

 their prey. Six species are recognized, four of which occur in the 

 northern hemisphere and two in the southern. 



Genus STERCORARIUS Brisson. 

 10. Stercorarius pomarinus (Temm.). 



POMARINE J^GER. 



Distr. : Seas and inland waters of northern part of northern hemi- 

 sphere; south in winter to Africa and Australia. Its winter range in 

 America is uncertain. 



Adult (light phase of plumage): Bill, over 1.35, tarsus, over 1.75, 

 upper parts, slaty gray, a tinge of pale yellow on the sides of the head 

 and neck; crown of the head and lores, sooty black; under parts, 

 white, shading into slaty gray on sides and lower belly; ends of two 

 middle tail feathers, rounded. 



Adult {dark phase ) .■ General plumage, sooty brown, slightly 

 paler below; crown, dark brown. 



Immature (light phase ) . Head and neck streaked with buff or 

 gray; under parts mottled and barred with slaty gray; upper parts, 

 dark gray; some of the feathers edged with buff. 



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