LOON. 85 



them when leaving the nest. The young are born covered 

 with down and can swim at birth. The Pied-billed 

 Grebe is one of our most aquatic birds. When pursued, 

 it prefers diving to flight, and the marvelous rapidity 

 with which it can disappear from the surface of the 

 water, to reappear in a quite unexpected place, justifies 

 its reliance on its own natatorial powers. It can swim 

 under water with only its bill exposed, when it becomes 

 practically invisible. 



When on land Grebes progress awkwardly. They 

 can, it is said, stand erect on their toes, but, when resting, 

 support themselves on the whole length of the foot or 

 tarsus (see Fig. 8, the Great Auk). 



On the wing Grebes resemble small Ducks, but their 

 pointed bill and their feet stretched out behind the rudi- 

 mentary tail will serve to distinguish them. 



LOONS. (FAMILY URINATORID^E.) 



The Loon, like its small relative the Grebe, is known 



to almost every one by name, but only those who have 



Loon visited its summer haunts among the 



Urinator imber. ^Northern lakes and heard its wild call 



Plate in. can ^e g^ ^- o k now ft Nuttall writes 



of its cry as "the sad and wolfish call of the solitary 

 Loon, which, like a dismal echo, seems slowly to invade 

 the ear, and, rising as it proceeds, dies away in the air." 

 It " may be heard sometimes for two or three miles, when 

 the bird itself is invisible, or reduced almost to a speck 

 in the distance." The Loon is as aquatic in habits as the 

 Grebe, but is much stronger on the wing. It migrates 

 by day, and probably also by night, and we may some- 

 times see it passing over a large, ducklike bird in 

 March and October. 



When on land, it is nearly helpless, progressing awk- 



