Species, Age and Sex Identification of Ducks Using Wing Plumage

King Eider

This species occurs only casually in the more northern states of the Atlantic Flyway. Although common in Alaska, few are shot. Only a few wings from known-aged birds were available for study. Therefore, although the information presented here is probably reliable, it should be used with caution. At present, a serious problem with king eiders is the lack of a reliable method for separating females and immatures of this species from the same age and sex classes of common eiders.

Wing Character	Male		Female
	Adult	Immature	Immature	Adult
Tertials	Entirely black, sharply curved, and acutely pointed	Very dark brown, usually edged with pale brown at tips only; tips are rather sharply pointed, often frayed and/or notched		Very dark brown, slightly curved, and acutely pointed
Greater tertial coverts	Broadly rounded and black	Usually narrowly edged with pale brown; often frayed at tips		Broadly rounded, very dark brown, broad pale brown edging
Greater secondary coverts	Black, often with some white tipping	Very dark brown; many white-tipped; and similar to those of adult female		Very dark brown, many white-tipped; rest solid brown slightly faded at tips
Middle and lesser coverts	Entirely white except for the leading edge of the wing	Similar to adult female but edging is darker and somewhat narrower		Broadly rounded, very dark brown, broad pale brown edging

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