108 SEA DUCKS. 



bill, as in the Anatitm, acts as a sieve or strainer. As a rule they feed 

 by day and pass the night at a distance from the shore or at sea. Some 

 of the species occur in our waters in large flocks indeed, our most 

 abundant Ducks are members of this subfamily. With one exception 

 they are northern breeding birds, seldom nesting south of our north- 

 ern tier of States. 



Their nest is composed of twigs, leaves, grasses, stems of aquatic 

 plants, seaweed, etc., lined with down from the breast of the incubat- 

 ing bird. 



KEY TO THE SPECIES. 



I. Feathers at the base of the bill not reaching -50 forward along its sides. 



A. Wing over 7 - 00 ; axillars and most if not all the linings of the wings white. 



a. Head and neck black, with greenish or purplish reflections. 

 a 1 . Back black ; bill with a bluish band near its tip. 



150. RING-NECKED DUCK $. 

 b l . Back finely barred with black and white. 



4*. Back of head generally with purplish reflections ; wing generally 

 under 8'25; nail of bill generally under -25 in width. 



149. LESSER SCAUP DUCK $ . 



b*. Back of head generally with greenish reflections ; wing gener 

 ally over 8'25 ; nail of bill over - 25 in width. 



148. AM. SCAUP DUCK $. 



b. Head and neck rufous or rufous-brown, sharply defined from the black 

 breast. 



b 1 . Head and upper neck rich rufous ; bill 2'00 or under ; flanks finely 

 barred, like the back 146. REDHEAD $ . 



b y . Head and neck rufous-brown ; crown blackish ; bill over 2 - 00 ; flanks 

 very slightly if at all barred 147. CANVASBACK $ . 



c. Head find neck brownish or grayish. 

 c l . A white patch in the wing. 



c*. Feathers at base of bill white; wing generally under 8'25; nail of 

 bill generally under '25 in width . . 149. LESSER SCAUP DUCK 9 



c*. Feathers at base of bill white; wing generally over 8'25; nail of 

 bill generally over -25 in width . . . 148. AM. SCAUP DUCK 9 - 

 d l . No white in wing. 



d*. An indistinct bluish band near the tip of bill ; bill under 2'00. 



</'. Wing under 8"00 150. RING-NECKED DUCK 9- 



d*. Wing over 8-00 146. RKDIIEAD 9 . 



*. No band on bill ; bill over 2'00 147. CANVASBACK 9 . 



B. Wing over 7'00; axillars and most if not all the under wing-coverU 

 blackish. 



a. Head and throat dark steel-blue or steel-green. 



a 1 . Head and throat steel-blue; white patch at base of bill 1-00 or more 



in height 152. BARROW'S G<>I.I>KN-KY i J, 



o. Head and throat steel-green ; white patch at base of bill less than 

 1-00 in height 151. AM. GOLDEN-EVE $ . 



