Species, Age and Sex Identification of Ducks Using Wing Plumage

Ring-necked Duck

Age Determination

Ring-necked duck wings should be examined under ideal lighting, preferably daylight rather than artificial light. A high fraction of immatures replace tertial coverts during the hunting season with shiny black feathers that differ slightly from the very dark brown of the other wing coverts. It may be necessary to tilt a wing back and forth to see this difference. If no difference is apparent and all tertial coverts are broadly rounded, the wing is from an adult. If, however, the tertial coverts tend to narrow toward their tips and/or appear frayed and/or notched, the wing is from an immature. Many of the middle and lesser coverts of immatures may also show notches.

Sex Determination

The sexes of approximately half of each age group can be identified from wing measurements provided all primary quills have hardened. Adults with a notch-length of 196 mm. or more are males and those with a notch-length of 188 mm. or less are females. Immatures with wings 194 mm. or longer are males while those with wings 184 mm. or shorter are females. There are a few exceptions to these measurements. There is too much overlap to permit accurate sex determination of adults with wings 189-195 mm. long or immatures with wings 185-193 mm. long using measurements alone.

Adult male tertials are shiny, greenish black and bluntly pointed. The tertials of adult females are similar but slightly less shiny, greenish brown and broadly rounded. Males are usually flecked (often faintly) on the underwing over the radius and ulna. Females are rarely flecked in this area. All of these differences are slight and accurate sex determination is quite difficult.. Because some immature males resemble immature females, sex determination of immatures is not completely reliable.

Wing Character	Male		Female
	Adult	Immature	Immature	Adult
Tertials	Dark blackish, often with faint greenish cast; droop to rounded tip	Blackish to dark brown, usually frayed to a ragged point; straight		Blackish brown, often with faint cinnamon cast; droop slightly to rounded tip
		After molt: Similar to adult male	After molt: Similar to adult female
Greater tertial coverts	Broadly rounded, dark blackish	Dark brown to blackish; usually narrow slightly to ragged tips		Broadly rounded, dark brown
		After molt: Similar to adult male	After molt: Similar to adult female
Middle and lesser coverts	Broadly rounded, dark gray-black	Narrow slightly toward tips which are often ragged and may be slightly notched; slightly browner than adults		Broadly rounded, dark brownish
Underwing	White flecking present on small coverts near leading edge of wing most pronounced near body		Small coverts near leading edge brownish, with white edging, rarely with trace of white flecking
Notch- length	88% > 193 mm.	88% > 189 mm.	86% < 189 mm.	88% < 192 mm.

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