BAY AND SEA DUCKS 199 
a. Back black; bill with a bluish band near its tip. 
50. Rinc-NECKED Duck 2. 
bl. Back finely barred with black and white. 
b?. Back of head generally with purplish reflections; wing gener- 
ally under 8°25; nail of bill generally under ‘25 in width. 
149. Lusser Scaup Duck ¢. 
b3. Back of head generally with greenish reflections; wing gener- 
ally over 8°25; nail of bill over ‘25 in width. 
148. GreatTeR Scaup Duck 2. 
b. Head and neck not black. 
b'. Head and neck rufous or rufous-brown, sharply defined from 
the black breast. 
b?. Head and upper neck rich rufous; bill 2°00 or under; flanks 
finely barred, like the back ....... 146. REDHEAD a 
. Head and neck rufous-brown; crown blackish; bill over 2°00; 
flanks very slightly if at all barred .. 147. CANVASBACK a 
ce. Head and neck brownish or grayish. 
c. A white patch in the wing. 
c3. Feathers at base of bill white; wing generally under 8°25; 
nail of bill generally under °25 in width. 
149. Lesszr Scaup Duck ¢. 
c', Feathers at base of bill white; wing generally over 8°25; 
nail of bill generally over ‘25 in width 
148. Greater Scaup Duck ¢. 
d?, No white in wing. 
d3, An indistinct luish pene near arene tip of bill; bill under 2°00. 
d4, Wing under 8°00. 150. Rinc-Neckep Duck 9. 
d’, Wing over 8'00....... ae ae Me B 146. RepHEAD 9. 
e. No band on bill; bill over 2°00 . . . 147. CANVASBACK 9. 
B. Axillars and most, if not all, the under wing-coverts blackish. 
a. Head and throat dark steecl-blue or steel-green. 
a', Head and throat steel-blue; white patch at base of bill 1°00 or 
more in height ........ 152. Barrow’s GOLDEN-EYE 3. 
a*. Head and throat steel-green; white patch at base of bill less 
than 1:00 in height ....... 151. Am. GOLDEN-EYE ¢. 
b. Head and throat not steel-blue. 
b'1. Whole head and throat brown, sharply defined from the gray 
or white neck; a white patch (speculum) i in the wing. 
b2, Nostril nearer the tip than the base A the bill. 
AM. GOLDEN-EYE 9. 
b3. Nostril in the middle of the bill. 
152. Barrow’s GOLDEN-EYE 9. 
c@. Head and throat not brown but with more or less black. 
c?. Whole head ‘and neck black. 
@. Plomage black .....4 0282545 163. Am. ScorErR 2. 
d@, Whole head and neck not black. 
a3, Crown-patch or cheeks white. 
di’, A white en on the top of the head and another on 
the nape asc ew ee we 166. SurF ScotTsr 3. 
ds, Middle of crown black, bordered by chestnut; front 
half of face white..... 155. HaRLEQuIN Duck ¢. 
é, Head and neck whitish, grayish, or brownish, no white in 
wing. 
e4. Bill over 1°25. 
e5, Feathers on culmen reaching much farther forward 
than those at sides of the bill . 166. Surr Scorsr 9. 
e®. Feathers on culmen hapa acre of any beyond 
those at sides of bill. ... .. 163. Am. Scorer 9. 
fi. Bill under 1°25, 
