FAM. LXII. AUKS, PUFFINS, ETC. 337 



ORDER XVII. DIVING BIRDS (PYGOPODBS) 



This is preeminently the order of water birds ; all species 

 are at home only in the water, and all species swim and dive 

 with perfect ease. The legs are situated at the tail end of the 

 body ; so in attempting to stand, the birds hold the body in an 

 erect position, and the tarsus and tail are often used as partial 

 supports. These birds are very awkward in their movements 

 on land, their method of progression being by a shuffling 

 motion. 



FAMILY LXII. AUKS, PUFFINS, ETC. (AlCIDjE) 



A family (30 species) of short-necked, marine divers with 

 peculiar, short bills and three full-webbed toes. The append- 

 ages to the bill, which are numerous and remarkable, are shed 

 after the breeding season, and so are practically never observed 

 in the United States, as the nesting grounds are in the far 

 north. These birds differ from the other divers in the use of 

 their wings as an additional aid in swimming under water. 

 They breed, often in immense colonies, in cold regions, and 

 migrate southward in winter. Most species are strong flyers, 

 and all are wonderful swimmers. All the species belong to the 

 northern hemisphere, and more than half are found along the 

 Pacific Ocean. They feed exclusively upon animal matter, 

 and are mainly silent birds. 



Key to the Species 



* Bill light-colored, and more than an inch high at base. (F.) 



* Bill dark-colored, and less than an inch high at base. (A.) 



A. Culmen about i inch long ; wing under 5J long 8. Dovekie. 



A. Culmen, 1 or more long. (B.) 

 B. Wing, 5^7 J long; nostril overhung by a horny scale. (E.) 

 B. "Wing, 7^-9 long ; nostril more or less completely hidden by dense, 

 velvety feathers. (C.) 

 C. Tail of pointed feathers ; bill nearly an inch high at base and much 



flattened sideways 7. Razor-billed Auk. 



C. Tail of rounded feathers ; bill less than | inch high at base. (D.) 

 apgar's birds. — 22 



