Gadwall

The Gadwall is a medium-sized dabbling duck found across much of the Northern Hemisphere, breeding in prairie and steppe wetlands and wintering widely on lakes, marshes, and reservoirs. At a distance, males can look plain grey, but up close they show intricate fine vermiculation across the body.

One of the most useful features for feather identification in this species is the white speculum patch, a small rectangular patch of white feathers on the inner wing that stands out clearly against the surrounding grey-brown and is a reliable clue even from a single feather.

Males also show a bold black rear end (undertail coverts) contrasting with the grey body, while females look more like a female Mallard but with the same telltale white speculum patch and a distinctive orange-sided bill.

Size and shape

• Medium-sized dabbling-duck contour and flight feathers, slightly smaller and more slender than Mallard feathers
• Squared, moderate-length wings typical of dabbling ducks

Color and pattern

• Male body feathers finely vermiculated grey, appearing plain grey at a distance but intricately patterned up close
• A chestnut-brown patch on the upper wing coverts in males, adjacent to the white speculum
• Speculum feathers crisp white, one of the most reliable Gadwall clues in either sex
• Undertail covert feathers solid black in males, sharply contrasting with the paler grey body
• Female body feathers mottled brown, similar to a female Mallard, but retaining the white speculum patch

Distinguishing from similar species

• The white speculum patch separates Gadwall from Mallard (which shows a blue speculum with white borders) and from most other grey-brown dabblers
• Male's black rear end against grey body is distinctive and not shared by other similarly sized dabbling ducks in the same range

Males show finely vermiculated grey body plumage, a chestnut patch on the wing coverts, and a solid black rear end, with a plain grey head lacking bold markings. Females are mottled brown overall, similar to a female Mallard, distinguished by the white speculum and an orange bill with a dark central culmen stripe. Juveniles resemble females. Molt includes an eclipse phase in males, during which they briefly resemble females before regaining breeding plumage, alongside a flightless wing molt period typical of ducks.

Breeds across the prairie regions of North America and the steppe and wetland zones of Europe and Asia, favoring shallow freshwater marshes, lakes, and ponds with abundant emergent vegetation. It winters on lakes, reservoirs, and coastal marshes across a broad range further south. Most populations are migratory, though some winter in temperate areas year-round.

Feeds mainly by dabbling and grazing on aquatic vegetation, often associating with diving ducks and coots, sometimes taking food items they bring to the surface. Nests on the ground in dense vegetation, often some distance from open water. Voice includes a nasal, croaking call in males and a Mallard-like quack in females, though generally quieter. The reliable white speculum patch makes Gadwall one of the easier dabbling ducks to confirm from a single wing feather.