REDHEAD 
Tertials of the adult plumage usually have rounded tips. Vermicu- 
lations near the tips are found only on males. Juvenile tertials are 
similar to those of adult females but are usually frayed to a point. 
The greater coverts of adults are broad and smoothly rounded especially 
over the tertials. Those of adult males are heavily flecked with white 
while those of females are unflecked or faintly flecked usually near 
their edges. Juvenile greater coverts are narrower, squared, often 
frayed to a point over the tertials and often with an indistinct pale 
edge over the secondaries. Those of immature males are usually faintly 
flecked while those of females are unflecked. The middle coverts of 
adults are broadly rounded, heavily flecked on males but plain or 
faintly flecked on females. Juvenile middle coverts are narrower, 
squared, and faintly flecked on males but unflecked on females. 
During the hunting season, immature birds often replace both their 
juvenile tertials and greater tertial coverts with first winter feathers. 
For a given sex, these new feathers are indistinguishable from those 
of adult birds but markedly different from the other greater and the 
middle coverts which are retained. 
With practice, redheads can be aged largely by tertial coverts. 
These feathers are in three categories: 1) adult type, similar to the 
surrounding coverts; 2) adult type, that are obvious replacements; and 
3) juvenile type. Sex also can be determined from the first two, but 
it becomes necessary to refer to the middle coverts to determine the 
sex of the third type. 
KEY TO REDHEAD WINGS 
1. Tertials and Scapulars: 
(a) Some show vermiculation ----------------------------- Male 2 
(b) No tertials show vermiculation, some scapulars 
may be heavily flecked (but not vermiculated) 
at their bases ----------------------------+------~-- 3 
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