108 



SEA DUCKS. 



i fJt 





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i: 



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

 by (lay 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. Featliers 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». Buck black ; bill with a bluish band near its tip. 



150. RlNO-NECKED DuCK $. 



6>. Back finely barred with black and white. 

 i». Back of hjad generally with purplish reflections; wing generally 

 under 8'io ; nail of bill generally under "J5 in width. 



149. Lessek Scaup Duck & . 

 Js. Back of liead generally with greenish reflections; wing gener- 

 ally over 8-2r); nail of bill over -2.") in width. 



148. .\m. Scaup Duck $ . 



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; flanks finely 

 barred, like the back , 140. Reumead 3 . 



6». Head and neck rufous-brown ; crown blackish ; bill over 2-00 ; flanks 

 very slightly if at all barred 147. Canvas»acr3. 



c. Head and neck brownisli or grayish, 

 c'. A white patch in the wing. 



t». Feathers at base of bill white ; wing generally under 8'2r) ; nail of 



bill generally under •2.'i in width . . 149. Lesser Scaup Duck 9 . 

 c». Feathers at l)ase of liill wliite ; wing generally over 8"25 ; nail of 



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

 </». No white in wing. 

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



(/». Wing under 800 150. Rino-nei ked Duck 9. 



(/*. Wing over 800 14(]. Reduead 9 . 



e». No band on bill ; l)ill over 2-00 147. Canvasback 9 • 



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

 blackish. 



o. Head and throat dark steel-iilue or steel-green. 

 «>. Head and throat steel-ljlue; white patch at base of bill l-OO or more 



in height 152. Bajjkow's Goi.oen-eve $ . 



tt«. Head and throat steel-green; white patcii at base of bill less tiian 



1*00 in heiglit 151. Am. Golden-evk 3 . 



