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 bufly 

 white. 



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



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

 or more ; length about 4 J-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 9 . 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 (YARK.). Bewick's Swan. 1 



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

 yellow spot. 



Length about 4 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. 

 J . 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 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 (Eicn.). Trumpeter Swan. 



' Oyffnui bewickii YABR., Trans. Linn. Soc. xvi. 1830, 453. Olor bewickii STEJN. Proo. U. S. Nat. Mus. v., 

 1882, 201. 



