Species, Age and Sex Identification of Ducks Using Wing Plumage
Separation of Redhead and Canvasback
Adult male canvasbacks have much more white on the upper surface of their wings
than any other age-sex category of redhead or canvasback. All other canvasbacks
have much darker secondaries than those of all redheads. Thus, the contrast between
secondary coverts and secondaries is greater on wings of redheads of all age and
sex groups than it is on the wings of adult female or immature canvasbacks of
either sex.