Species, Age and Sex Identification of Ducks Using Wing Plumage

Mottled Duck

Because mottled ducks are southern nesters, most immatures have replaced both tertials and greater tertial coverts at the time hunting occurs. Careful scrutiny, however, will usually reveal one or more faded coverts in this area. These are remnants of the immature plumage. Sexual identification is difficult. Wings of males are generally longer than those of females, but there is considerable overlap. Birds with three or more non-iridescent secondaries are virtually all females, but birds with only one or two non-iridescent secondaries may be of either sex. The greater tertial coverts of females tend to more heavy edging than those of males, but the two types grade together.

Wing Character	Male		Female
Wing Character	Adult	Immature	Immature	Adult
Tertials	Usually acutely pointed; covert to tertail tip often > 90 mm; lack internal markings	Similar to adult males; lack internal markings	Similar to adult females; internal markings often present	Often bluntly pointed; internal markings often present
Greater tertial coverts	Broadly rounded; edging varies from broad to narrow	Usually similar to those of adult males; often one or more narrow and frayed or faded	Usually similar to those of adult females; sometimes one or more narrow and frayed or faded	Broadly rounded with heavy tan edging
Secondaries	Normally, only one or two are not at least partly iridescent	Normally, only one or two are not at least partly iridescent	Approximately 80% of the wings have at least 3 non-iridescent feathers	Approximately 75% of the wings have at least 3 non-iridescent feathers
Notch- length	81% > 255 mm.	84% > 251 mm.	81% < 250 mm.	86% < 254mm.

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