OIDEMIA. m 



b 1 . Nail of bill much flattened, scarcely hooked at tip. Adult male: Bill black 

 with a yellow or orange spot on culmen immediately in front of the 

 basal knob. Adult female : Above sooty brown, beneath paler, inclining 

 to light grayish brown on breast and belly ; bill wholly dusky, the basal 

 half of the culmen level, or scarcely -if at all elevated at base. "Wing 

 8.00-9.20, culmen 1.90, depth of upper mandible at base .98-1.00 in male, 

 .50 in female, tarsus 1.50-1.60. Sab. Northern portions of eastern hemi- 

 sphere. 



O. nigra (Linn.). European Scoter. 1 

 b 2 . Nail of bill distinctly arched, and decidedly hooked at tip. Adult male: 

 Basal half of upper mandible, including whole of knob, yellow or 

 orange ; rest, including entire edge, black. Adult female : Above dusky 

 grayish brown, the feathers of dorsal region with paler tips; lower 

 parts paler grayish brown, the lighter tips broader, though want- 

 ing on the posterior portions ; lateral and under-parts of head nearly 

 uniform light grayish brown, in decided contrast with dark brown of 

 pileum and nape; bill uniform blackish. Young: Much like adult 

 female, but lighter beneath, where indistinctly barred (mostly beneath 

 the surface) with grayish brown. Length 17.00-21.50, wing 8.75-9.50, 

 culmen 1.65-1.80, depth of upper mandible at base .85-.95 in male, .70 

 in female, tarsus 1.65-2.00. Eggs 2.55 X 1-80, pale dull buff or pale 

 brownish buff. Sab. North America, breeding northward ; in winter, 

 south to New Jersey, the Great Lakes, and California. 



163. O. americana Sw. & Bich. American Scoter. 

 a 1 . Length of commissure much more than length of inner toe without claw. 



b 1 . Feathering of head advancing much farther forward on lores than on fore- 

 head ; sides of upper mandible at lower portion of base sunken ; wing 

 with a white speculum. (Subgenus Melanitta Boie.) 

 c 1 . Loral feathers separated from nostril by a space nearly or quite 

 equal to length of nostril ; male with lower part of swollen basal 

 portion of upper mandible, on sides, unfeathered; sides of bill 

 orange-yellow in life ; basal portion of culmen elevated but not 

 forming an abrupt knob ; plumage uniform black, or brownish 

 black, relieved by a white wing-speculum and a white patch be- 

 neath and behind eye. Adult female : Sooty grayish, or dusky 

 grayish brown, darker above ; wing with a white speculum, but no 

 white on head ; bill wholly dusky. Downy young : " Crown, nape, 

 hind-neck, and sides of the head to a line from the base of the 

 lower mandible deep brown; a small white spot below the eye; 

 upper parts uniform dark brown with an olivaceous tinge ; a small 

 white patch of down on the wings ; under-parts white, the upper 

 breast crossed by a dull brown band." (Dresser.) Length about 

 21.00, wing 10.65-11.40, culmen 1.40-1.70, depth of upper mandible 



l Anas nigra Likn., S. N. ed. 10, i. 1758, 123. Oidemia nigra Flem., Brit. Anim. 1828, 119. 



