
LESSER SCAUP 
Sex Determination 
Scapulars of adults of both sexes may be vermiculated. Those of 
adult males are more white than dark. Those of all females are more 
dark than white. Scapulars of immature males are often female-like 
but usually have one ot more male-like feathers. The tertials of all 
adult males and many immature males are flecked. Female tertials are 
plain or, on a small number of adults, have a few flecks near the tips. 
The greater and middle coverts are plain on most immature and on many 
adult females. Those of males are heavily flecked or vermiculated. 
Flecking on female wings is usually much finer and tends to be concen- 
trated near the edge of individual coverts, Flecking on immature male 
wings is larger, covers the entire covert, or tends to be recessed 
from the covert's edge. Adult males generally have vermiculated 
coverts. 
Age Determination 
Tertials of the juvenile plumage are frayed to a pointed tip. 
Tertials of the adult plumage are usually round tipped but often 
similar to juvenile tertials. CAUTION: diving duck tertials are 
somewhat unreliable. The greater coverts of adults are broadly 
rounded and shiny black. Over the tertials, those of males are usually 
flecked, but those of females are plain. Juvenile greater coverts are 
Narrower, and usually frayed and dull black. A few immature males may 
have flecking over the tertials but most do not. Females have unflecked 
greater coverts. 
Juvenile tertials and greater tertial coverts are not replaced 
during the hunting season iM most instances. 
KEY TO LESSER SCAUP 
Sex Determination 
1. Upper Wing: 
(a) Any or all of the following: One or more of the 
vermiculated scapulars are more white than black. 
Tertials are flecked or vermiculated. The greater 
coverts are flecked and are broadly rounded 
particularly over the tertials -------------------- Male 
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