Bird of the Month: Gadwall

By High Jennings

Scientific Name: Anas strepera

Length 20 in

Wingspan 33 in

AOU Band code GADW

The Gadwall (GADW) is a duck about 20” long with a wingspan of 33”. The genus name Anas (AY-nas) is Latin, for duck. The species name strepera (STREP-eh-rah) is from Latin, streperus, noisy, apparently in reference to loud calls of the female. The female does a quacking sound, and higher-pitched decrescendo than the Mallard. The male gives a whistle and “raeb-raeb” call. The name Gadwall, the common English name of this duck, is of obscure origin.

The Gadwall is one of the least distinctive dabbling ducks when seen at a distance, but close views reveal the subtle but beautiful colors. The best mark of the male is the contrast of the black rear end feathers with the gray body and white belly; the brownish head and neck are less distinctive. In flight the Gadwall displays a white speculum (see photo), the only dabbler to do so. The female’s mottled brown plumage resembles the female Mallard, but the belly is white, forehead is steeper and bill is gray with orange sides.
The GADW is widespread in North America and in Europe and Asia, but is most common on inland waters west of the Mississippi River. In summer, it is usually found around fresh or alkaline lakes and ponds in prairie regions or western intermountain valleys where land is open, not forested. In winter and during migration, it is usually found on marshes, lake and estuaries, but generally not on salt water. In Washington state, it is a common resident and especially numerous around Puget Sound. It is much less common on the Eastside in winter.

The Gadwall feeds by tipping body tail-up and by diving for food. It mainly feeds on aquatic plants, but compared with other dabbling ducks, it eats more leaves and stems of plants and fewer seeds. It also eats small numbers of mollusks, insects, crustaceans, and rarely small fish. Very young ducklings eat many insects at first before changing to a more vegetarian diet.

During courtship, one of the many male displays involves pulling the head far back on shoulders and raising rear part of body out of water, with wingtips lifted to show off white patch and wing. The female, accompanied by the male, makes prospecting flights to seek a nest site. This is usually near water, on dry land, and surrounded by dense weeds or grass. The nest is built by the female in a shallow depression and is made of grasses and weeds, lined with down. There can be from 7-13 white eggs. Two or more females may lay eggs in the same nest. Incubation is by the female only and lasts 24-27 days. The young leave the nest shortly after hatching. The female leads the young to water, where they find their own food. The young are capable of flight 48-59 days after hatching.