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 

 water, except during the nesting season. 



Summer 



Loons. 



Winter. 



Genus GAVIA Forster. 



7. Gavia immer (BRUNN.). 

 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 



