Both sexes have grey wings with black primaries and a white speculum feathers.

The speculum feathers are greenish-blue, bordered on both sides by white.

The north-eastern race is darker and has a brighter bill and blue speculum feathers.

The wing has an iridescent purplish-green patch (speculum feathers) in both sexes.

The breeding male has grey flanks and back, with a yellow rear end and a white-edged green speculum feathers, obvious in flight or at rest.

The speculum feathers are green as in some of its relatives, but unlike in these, it is bordered white as in the Mallard.

Both male and female Mallards have distinct iridescent purple blue speculum feathers edged with white, prominent in flight or at rest, though temporarily shed during the annual summer moult.

The wings are coloured similar to the drake's, but with brown instead of grey upperwing coverts that have less wide tips, and wider tips of the speculum feathers.

Between three to four months of age, the juvenile can finally begin flying as its wings are fully developed for flight (which can be confirmed by the sight of purple speculum feathers).

The wing patch (speculum) and the tail was also like in mallard drakes' nuptial plumage, including curled-up central tail feathers, but the tips of the speculum feathers were buff.

The primary remiges are dark greyish brown; the speculum feathers are iridescent blackish-green with white tips, and form the speculum together with the yellowish-white tips of the larger upperwing coverts (which are otherwise grey).

As part of his courtship, for example, the male Garganey touches his beak to the blue speculum feathers on his wings in a fake preening display, and the male Mandarin Duck does the same with his orange sail feathers.