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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

JPG-Adult male hooded merganser JPG-Adult female hooded merganser JPG-Immature hooded merganser

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