Species, Age and Sex Identification of Ducks Using Wing Plumage

Hooded Merganser

Sex Determination of Adults

Adult males have shiny black, unfrayed tertials with longitudinal white stripes and light gray middle and lesser coverts. Adult females have shiny black tertials with longitudinal white stripes, which, while tapering (as in males), are slightly shorter and blunter. The middle coverts of females are a blackish brown to grayish.

Age Determination

Immatures are similar in gross aspect to adult females, but immature tertials are straight and frayed at the tip and often appear brown. The middle and greater coverts usually are frayed and brown, particularly over the tertials. These feathers are smooth and unfrayed on adults.

A few immatures can be identified as males by the presence of one or more light gray middle or lesser coverts emerging among the darker feathers; however, the sex of most immatures cannot be determined.

Wing Character	Male		Female
	Adult	Immature	Immature	Adult
Tertial	Black; with broad longitudinal white stripes at rachis; acutely pointed; curve distally	Dark brown; three distal with longitudinal white stripes at rachis; shafts straight; tips acutely pointed and very frayed		Black; three distal with longitudinal white stripe at rachis; acutely pointed; curve distally
		After molt: Similar to adult male	After molt: Similar to adult female
Tertial coverts	Black and pointed	Dark brown and pointed; often frayed and faded		Black and pointed
Greater coverts	Broadly banded at tips with sharply defined white	Variably banded at tips with white which is often poorly defined and frequently with dark edging		Broadly banded at tips with sharply defined white
Middle and lesser coverts	Do not cover black basses of greater coverts
	Pale grey, broadly rounded over secondaries	Dark brown; tips often ragged and frayed		Broadly rounded; dark brown but slightly paler distally

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