342 



KEY AND DESCEIPTION 



of the body. There are four toes, the three in front being full 

 webbed. In summer, all species when adult have the dark 



back regularly spotted with 

 '' ~ "" ~^ nearly square white blotches. 



I They are all migratory, breed- 

 ing, with one exception, in the 

 Arctic regions, but found in 

 the United States in winter. 

 These birds, like all the div- 

 ers, are exceedingly clumsy 

 on land, which they seldom 

 visit except for breeding pur- 

 poses ; but in the water their 

 powers of swimming and div- 

 ing are only equaled by the 

 grebes. They are also strong 

 and rapid ilyers. In their 

 migrations, they keep at a 

 considerable height and are 

 usually seen in small flocks. 

 In pursuit of fish, which forms their only food, they move 

 through the water by the aid of their feet alone. In this 

 they are like the grebes, but unlike the auks. 



Loon 



Key to the Species 



* Wing, 13-16 long ; tarsus, .3-3^; culraen, SJ-SJ 1. Loon. 



* Win.L', 10-13}; tarsus, 2i-3; culmen, 2-2|. (A.) 



A. Adult in summer, tliroat black ; adult in winter and young, no 



wliite spots on the back, but grayish margins to the feathers 



2. Black-throated Loon. 



A. Adult in summer, throat gray with a triangular, chestnut patch ; 



adult in winter and young, back distinctly spotted with white 



3. Red-throated Loon. 



1. Loon (7. Urinutor Imber). — Adidt in summer, a very large, 

 greenish-black-headed, black-throated loon, with the breast and 

 belly white. The back and wings are greenish-black, with 

 many nearly square, white spots. There are spaces on the 



