The Gadwall (Mareca strepera) is one of the more understated dabbling ducks, a medium-sized bird — clearly bigger than a Teal but a touch smaller than a Mallard — in muted grey-brown tones that lack the flashy head colours of its relatives. The drake is subtly handsome, with finely vermiculated grey plumage on breast and flanks, a brown head with a darker eye patch, a black rear end and undertail, and orange-tinged flanks. The female is mottled brown in typical dabbling-duck fashion and closely resembles a female Mallard, but has a more clearly orange-edged bill. In every plumage, both sexes reveal a white wing patch (speculum) that flashes conspicuously in flight and is the single most reliable field mark for the species, distinguishing it from the blue speculum of the Mallard and the green one of the Teal.
The female's call is a distinctive, mocking "gack-gack-gack" — drier and faster than a Mallard's quack — while the drake gives a low, croaking "nhech" during display that is easy to overlook. In Sweden the Gadwall is concentrated in the richest lakes and fens of the southern and central regions, with strongholds such as Tåkern and Hornborgasjön, and the population of some 5,000–10,000 breeding pairs has been growing thanks to newly created wetlands. Nests are well hidden in dense waterside vegetation, where the female lays 8–12 cream-coloured eggs and incubates alone for 24–26 days before leading the precocial ducklings straight to the water. Gadwalls feed mainly on aquatic plants and their green parts, dabbling at the surface and straining submerged vegetation such as pondweed and bur-reed, supplemented by seeds and invertebrates, especially during the breeding season. Across the wider region they breed in a broad, discontinuous band from Iceland through Europe and Asia to Japan, wintering around the Mediterranean, in North Africa and South Asia.
Read about this species in Swedish →