108 SEA DUCKS. 



bill, as in the Anatinm, 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 menjbers of this subfamily. With one exception 

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

 ern tif r 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. 

 u. Head and neck black, with greenish or purplish refiectious. 

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



150. ElNG-NEOKED DuOK 6 . 



i'. Back iinely barred with black and white. 

 }». Back of head generally with purplish reflections ; wing generally 

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



149. Lesser Scaup Dtjck $ . 

 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 S ■ 

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

 breast. 

 6'. Head and upper neck rich rufous ; bill 2-00 or under ; flanlcs finely 



barred, like the back. . 146. Eedhead S. 



i'. Head and neck rufous-brown ; crown blackish ; bill over 2-00 ; flanks 



very slightly if at all barred 147. Cauvasbaok i . 



V. Head and neck brownish or grayish. 

 c^. 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. Lessee Soacp Duok 9 . 

 c>. Feathers at base of bill white ; wing generally over 8-25 ; nail of 

 bill generally over -25 in width . . . 148. Am. Scaup Dock 9. 

 (?i. No white in wing. 

 d^. An indistinct bluish band near the tip of bill ; bill under 2-00. 



d'. Wing under 8-00 150. Einq-necked Duok 9 . 



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



e^. No band on bill ; bill over 2-00 . . . . 147. Canvasbaok 9 . 

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

 blackish. 



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

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



in height 152. Barrow's Golden-eye i . 



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

 1-00 in height 151. Am. Golden-eye i . 



