20 KEY TO DUCKS, GEESE AND SWANS OF NORTH AMEEICA. 



A patch of white or grayish white on the head, including the eye ; no specu- 

 lum ; under tail coverts, white ; adult males have the tail feathers long and 

 pointed. 



Old Squaw. Long-tailed Duck. 



Olangula hyemalis. 



See page 64. 



Section 5. Hind toe with well defined membraneous lobe 

 or flap; belly, white, sometimes tinged on lower part 

 with dusky or gray ; no white or grayish white on head. 



Head, brown. 



Glaucionetta clangula americana (female). 

 See page 59. 



Glaucionetta clangula 

 americana. 



Head, black, glossed with green ; speculum, white ; back, grayish white 

 finely lined with black. 



Oreater Scaup Duck. 

 Blue-bill or Black Head. 



Aythya marila nearctica (male). 

 See page 56. 



Head, black, glossed with purple, finely lined with black ; speculum, white ; 



back, grayish white, smaller than the preceding species, but resembles it closely. 



Lesser Scaup Duck. 

 Blue-bill or Black-head. 



Aythya affinis (male) . 

 See page 57. 



Head, black, with violet or bluish gloss, a spot of white on the chin; specu- 

 lum, gray ; back, dull black. 



Ring-necked Duck. 



Aythya collaris (male) . 

 See page 58. 



Section 6. Hind toe with well defined membraneous lobe 

 or flap; belly, not white. 



Plumage, variously marked with white, slate-color and chestnut; speculum, 

 bluish ; top of head and wing coverts, not white. 



Harlequin Duck. 



Histrionicus histrionicus (male) . 

 See page 66. 



