WOOD DUCK 
Sex Determination 
The tertial coverts of females are pink while the tertial coverts 
of males are a dark purple. On very young birds of either sex, these 
feathers may be a yellow green. The trailing edge of the wing second- 
aries of females of all ages forms a white "tear drop" while this 
edging is white but flat and evenly distributed on males. 
Age Determination of Males 
The juvenile tertials of males are pale bronze usually with 
pointed frayed tips. The tertials of the adult and first winter 
plumage are a deep purple with somewhat squared ends. Juvenile 
tertials are usually replaced by mid-October. 
Both the middle coverts and greater coverts of the juvenile male 
plumage are much duller purple than are those of the adult plumage. 
As the juvenile plumage is replaced by the first winter plumage, the 
presence of a few very dark purple feathers among the duller coverts 
indicates immaturity. The dark purple gradually spreads over the 
wing but usually does not extend onto the second row of middle coverts 
and is also much restricted to the area anterior to the tertials. 
Individual juvenile coverts possess dark terminal borders that tend 
to be slightly wider near the shaft while adult coverts have a uni- 
form border. Adult coverts appear somewhat larger and smoother than 
do those of immatures. The most proximal greater covert of the 
juvenile plumage appears greener, duller, and usually smaller, than 
does the corresponding feather of the adult or first winter plumage. 
Age Determination of Females 
The juvenile tertials of females are similar in shape and color 
to the juvenile male tertials. Adult female tertials and immature 
first winter tertials are also a pale bronze but have rounded instead 
of pointed, frayed tips. 
The tertial coverts of extremely young birds often are small and 
greenish yellow but they are soon replaced by the pink tertials of 
the first winter plumage which is similar to that of adult females. 
Some metallic blue is usually present on the second row of the 
middle coverts and this coloring extends distally over two-thirds of 
the secondary coverts. Metallic-blue coloring usually does not extend 
onto the second row of middle coverts nor so far distally on the wings 
of immature birds. Adult coverts appear somewhat larger and smoother 
than those of immatures. 
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