Species, Age and Sex Identification of Ducks Using Wing Plumage

American Black Duck

Age Determination

Because wings of the sexes are similar, it is easier to determine the age of black ducks before attempting to identify their sex. Tertials small, narrow, and frayed and/or faded near their tips are remnants of immature plumage. Adult tertials are longer and wider and are not frayed or faded. Tertial coverts of the immature plumage tend to be narrow, somewhat trapezoidal, and frequently frayed and/or faded. Those of adults are wide, broadly rounded, and rarely frayed or faded. During their first fall and winter, a substantial fraction of the immatures may replace both their immature tertials and tertial coverts with adult-type feathers. Thus, it is important to look closely at the middle coverts immediately anterior to the tertial coverts for indications of the trapezoidal shape, duller color, and wear that indicate immaturity. Primary coverts of many immatures have light edging on their inner webs. This type of edging does not occur on adults.

Sex Determination of Adults

Adult male tertials are more than 90 mm. long from the edge of the longest tertial covert to the tertial tip, and acutely pointed with some pearly color on the outer webs. Tertial coverts have broad edging which is pale brown. Middle and lesser coverts are broadly rounded and unfrayed. The notch-length of 94 percent of the adult male known-age specimens was greater than 281 mm.

Adult female tertials are less than 90 mm. from the edge of the longest tertial covert to the tertial tip, and they are rather bluntly pointed. Pearly color generally does not occur on the outer webs. Tertial coverts have broad edging which is pale brown. Middle and lesser coverts are broadly rounded and unfrayed. The notch length of 94% of adult females was less than 281 mm.

Immature tertials less than 88 mm. from the longest covert to the tertial tip are from females and longer tertials are from males.

Wing Character	Male		Female
	Adult	Immature	Immature	Adult
Tertials	Broad; tips often acutely pointed; usually pearly gray-brown colored; no edging to narrow light edging; not frayed or faded	Small; narrow; often frayed or faded		Broad; tips often bluntly pointed; rarely pearly colored; usually wide to narrow light edging; not frayed or faded
		After molt; Similar to adult male	After molt; Similar to adult female
Greater tertial coverts	Broad; often light edging; tips are smoothly arced; not frayed or faded	Often somewhat narrow and trapezoidal; may be frayed or faded		Broadly rounded; usually more light edging than males; tips are a smoothly rounded arc; not frayed or faded
		After molt; Similar to adult male	After molt; Similar to adult female
Middle and lesser secondary coverts	Tips form smoothly rounded arcs; may have light edging or no edging	Slightly triangular to trapezoidal; often somewhat frayed or faded; may have edging or no edging; tendency toward edging only on tips		Tips form smoothly rounded arcs; may have light edging or no edging
Greater primary coverts	Four most distal do not have light edging on inner webs	Four most distal often (but not always) have light edging on inner webs		Four most distal do not have light edging on inner webs
Notch- length	94% > 281 mm.	93% > 273 mm.	94% < 273 mm.	94% < 281 mm.

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