(e3 KEY TO THE BIRDS OF EASTERN NORTH AMERICA. 
Head, greenish purple, no white on head; back, dull black; speculum, gray (male). 
Aythya collaris. Ring=neck Duck. 
See No. 107. 
Head, dull brown, browni-h white at base of bill and below eye: speculum, gray 
(female). Aythya collaris. Ring=neck Duck. 
See No. 107. 
Head, greenish purple, a large patch of white on back of head (male). 
Charitonetia albeola. Buffle=headed Duck. 
See No. 110. 
Head, dark brown or dusky, a patch of white behind the eye (on ear coverts): no 
white or brownish white at base of bill; speculum, white (female). 
Charitonetta albeola. Buffles=headed Duck. 
See No. 110. 
Section 2. Belly, not white. 
Plumage, variously marked with white, slate-color, and chestnut (male). 
Histrionicus histrionicus. Harlequin Duck. 
See No. 112. 
General plumage, dull brown, mottled on the under parts (female). 
Histrionicus histrionicus. Harlequin Duck. 
See No. 112. 
Head, mostly white, greenish on lores and occiput (male). 
Eniconetta stelleri. Stellers’ Duck. 
See No. 114. 
Head, light brown; belly, clear, sooty brown (female). 
Eniconetta stelleri. Stellers’ Duck. 
See No. 114. 
* Group 3. Wing, from 7.50 to 8.50 inches long. 
Section i. Head, marked with more or less white or 
brownish white; belly, white, sometimes tinged with 
dusky or gray on lower part. 
Head, brownish ; a patch of dull white on face at base 
of bill; speculum, white (female). 
Aythya marila. Greater Scaup Duck. Blue=bill. 
See No. 105. 
Aythya marila nearctica, 
Speculum, white, similar to preceding but somewhat smaller (female). More common in 
the South than the Greater Secaup Duck. Aythya afinis. Lesser Scaup Duck 
See No. 106. 
* For directions for measurement, see page 9. 
