282 Field Museum of Natural History — Zoology, Vol. IX. 



Family GAVIID^. Loons. 



The Loons are a small family, consisting of one genus and five 

 species, three of which occur on Lake Michigan. They feed prin- 

 cipally upon fish and are expert divers and swimmers, rarely leaving 

 w^ater, except during the nesting season. 



Summer 



Loons. 



Wintsr. 



Genus GAVIA Forster. 



7. Gavia immer (BRiJNN.). 

 LooN. 



Urinator imber (Gunn.), A. O. U. Check List, 1895, p. 3. 



Distr.: Ranges throughout the northern part of the northern 

 hemisphere, breeding from the northern United States northward; 

 south in winter to the Gulf of Mexico and Lower California. 



Adult in summer: Head and neck, black, showing green in some 

 lights; a patch of white, streaked with black, on the throat and sides 

 of the neck ; under parts, white ; back, streaked and spotted with white. 



Adult in winter, and immature: Head, grayish; throat, white or 



