120 NORTH AMERICAN BIRDS. 



Genus OLOR Wagler. (Page 88, pi. XXIX., fig. l.)< 



Species* 



Common Characters. — Adults with whole plumage pure white, the head often 

 stained with rusty ; bill either entirely black, or black and yellow ; iris dark brown ; 

 feet black. Young ashy, sometimes tinged with brownish, the bill flesh-color (or at 

 least partly of this color), and feet grayish, or whitish. Eggs* white or buffy 

 white. 



a\ Distance from the anterior corner of the eye to posterior end of the nostrils 

 much greater than from the latter point to the tip of the bill. 

 b 1 . Basal portion of bill and entire lores yellow in adult. 



c 1 . Yellow of bill surrounding nostrils ; wing 23.00 or more, and culmen 4.00 

 or more ; length about 4J-5 feet, extent 7-8 feet, wing 23.00-26.00, 

 culmen (including naked space on forehead) 4.00-4.75, tarsus 4.00, 

 •middle toe 5.00-6.00. Eggs 4.28 X 2.88. Hab. Northern parts of 

 eastern hemisphere ; occasional in southern Greenland. 



175. O. cygnus (Linn.); Whooping Swan. 



c s . Yellow of bill not extending as far forward as the nostrils ; wing less 



than 23.00, and culmen not more than 3.50 ; length less than 4 feet, 



extent about 6 feet, wing 20.00, culmen 3.50, tarsus less than 4.00, 



middle toe 4.50. Hab. Northern portions of eastern hemisphere. 



O. bewickii (Yarr.). Bewick's Swan. 1 

 J 2 . Basal portion of bill, with lores, black, the latter usually with a small 

 yellow spot. 



Length about 4J feet, extent 7 feet, wing 21.00-22.00, culmen 3.80- 

 4.20, tarsus 4.00-4.32, middle toe 5.40-5.90. Eggs 4.19 X 2.72. Hab. 

 North America in general, breeding far northward ; casual west to 

 Commander Islands, Kamtschatka ; accidental in Scotland. 



180. O. columbianus (Ord). Whistling Swan. 

 a 1 . Distance from anterior corner of eye to posterior end of nostril not greater than 



from the latter point to the tip of the bill. 



Bill and lores entirely black ; length 5-5J feet, extent 8 to nearly 10 feet, 

 wing 21.00-27.50, culmen 4.30-4.70, tarsus 4.54-4.95, middle toe 6.00- 

 6.50. Eggs 4.46 X 2.92. Hab. Interior of North America, more rare or 

 less generally distributed toward the Pacific coast, rare or casual along 

 the Atlantic coast ; breeding from Iowa and Dakota northward. 



181. O. buccinator (Kick.). Trumpeter Swan. 



1 Cygnus bewickii Yarr., Trans. Linn. Soo. xvi. 1830, 453. Olor bewickii Stein. Proo. U. S. Nat. Mus. v., 

 1882, 201. 



