288 Field Museum of Natural HtsTORv — Zoology, Vol. IX. 



Michii;au duriuLi winter." ((Jrnitholo.a;y <»l Illinois, 1895, p. 217.) A 

 bird of this species was shot on the Mississippi River near Keokuk, 

 Iowa, October 6, 1896; and the specimen is preserved in the collection 

 of Mr. William G. Praeger. (Anderson, Birds of Iowa, 1908, p. 153. ) 



The Parasitic Jaeger may be distinguished from the Pomarine 

 Jaeger by its shorter bill (less than 1.35) and having the middle tail 

 feathers pointed, not rounded at the ends as in S. pomarinus , and from 

 the Long-tailed Jaeger bv having the cere longer than the di.stance 

 from its end to tip of bill. 



Skua, Megalestris skua {Briiiin.). Mr. Ridgway included this 

 species in his Ornithology of Illinois (1895, p. 212), but I find no 

 record of its occurrence in Illinois. It is a north Atlantic species, 

 which is rare on the Atlantic coast of North America. 



Family LARID.^. Gulls and Terns. 



The Gulls and Terns are a cosmopolitan family, numbering about 

 seventy species. They are true water birds, being rarely found away 

 from its vicinity. Many species occur both along the coasts and on 

 the lakes of the interior. They usually breed in colonies, making their 

 nests upon the ground or on ledges of rocks and cliffs (rarely in trees ) . 

 They feed principally upon fish, but at times some species eat the 

 young and eggs of other birds, and occasionally small mammals. The 

 Gulls are in most cases larger than the Terns and much less graceful. 



C, laiirnus Gull. 

 llcriing Gull, 



Great Black-backed Gull. 

 Bonaparte's Gull 



