SWANS* 



SUB-FAMILY Cygnince. 



The swans are the largest of our water fowl, and the 

 American species measure nearly or quite five feet in 

 length. The naked skin of the bill runs back to the 

 eye, covering the lores ; the bill is high at the base, but 

 broad and flattened toward the tip ; the tarsus is reticu- 

 late, and shorter than the middle toe. In our species 

 the feathers do not come down to the tibio-tarsal joint. 

 The two American species are white in the adult plum- 

 age, the immature birds being gray. 



Both species belong to the restricted genus Olor, 

 which is distinguished from the true Cygnus by not 

 having a tubercle at the base of the bill. Thus in the 

 ornithologies, and in the American Ornithologists' 

 Union Check List, the generic name is given as Olor, 

 but the term Cygnus will answer the purposes of this 

 volume. 



Although the two swans are much alike, they may 

 readily be distinguished by the characters to be here- 

 after given; that is to say, the number of the tail feath- 

 ers and the position of the nostril opening in the bill. 



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