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 | ||
| 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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