120 NORTH AMERICAN BIRDS. 



Genus OLOR Wagler. (Page 88, pi. XXIX., fig. 1.) 



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 buff'y 

 w^hite. 



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^. Basal portion of bill and entire lores yellow in adult. 



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

 or more; length about 4|-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. Hah. Northern parts of 

 eastern hemisphere ; occasional in southern Greenland. 



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



c". 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. Hah. Northern portions of eastern hemisphere. 



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

 61 Basal portion of bill, with lores, black, the latter usually with a small 

 yellow spot. 



Length about 4| feet, extent 7 feet, wing 2L00-22.00, culmen 3.80- 

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

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

 Commander Islands, Kamtschatka ; accidental in Scotland. 



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

 a^ 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 5-5 i feet, extent 8 to nearly 10 feet, 

 wing 21.00-27.50, culmen 4.30^.70, tarsus 4.54-4.95, middle toe 6.00- 

 6.50. Eggs 4.46 X 2.92. Hah. 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 (Eich.). Trumpeter Swan. 



1 Cygnus hewickii Yarr., Trans. Linn. Soc. xvi. 1830, 453. Olor bewickii Stejn. Proc. U. S. Nat. Mus. v., 

 1882, 201. 



