WHITE-WINGED SCOTERS (continued) 
3. Greater Coverts: 
(a) Approximately one-half of the normally visible 
portion white, bases of these feathers blackish 
brown sharply delineated from white upper portion - Adult Female 
(b) Often only tips white, sometimes no white, bases 
brownish black not sharply delineated from white 
upper “povtiOn, .-=Ssr SSeS ses cee m es SS  ae Immature 
SPECIES SEPARATION OF OLDSQUAWS, 
SURF AND AMERICAN SCOTERS 
1. Two Most Distal Primaries (figure 1): 
(a) 10th primary shorter than 9th primary and either 
black and attenuated,or gray~black and tapering 
but much narrower than 9th primary --------------- American Scoter 
(b) 9th primary is the longest, outerweb of this 
feather narrows near tip ------9----<e- eee ee Oldsquaw 
(c) 10th primary longest,all primaries are 
uniformly tapering ----------- fee eee ee nen n-ne ne Surf Scoter 


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figure 1 
43 
