15" long, 6-1/2" high, 6-1/2" wide.
are medium-sized, streamlined ducks with mottled brown-and-black
body plumage and light brown heads. Females and males in eclipse
plumage may look superficially similar to Mallards. Both sexes
have a black and white wing-patch, or speculum, that is distinctive
in flight. Males also have chestnut on the forewing. Males in
breeding plumage have gray and black striations on their bodies
and heads, and black rumps. Females, immatures, and eclipse-plumaged
males have thin, black bills with orange on the sides, while
males in breeding plumage have solid black bills.
and marshes are the preferred habitat of the Gadwall, which is
often found in deeper water than many other dabblers. In western
Washington, it is associated with developed and cleared areas
and, on Puget Sound, shows a preference for urbanized habitats
over less developed areas. Gadwalls are often found at sewage
forage mainly while swimming, either taking items from the surface
or dabbling in shallow water, or diving, which they are more
likely to do than most other dabblers. They often follow American
Coots, foraging on plants that have been brought up to the surface.
Gadwalls seldom forage on land. They are more strongly monogamous
than other ducks, with over 90% paired by November, 4 to 5 months
prior to the breeding season. This monogamy is limited, however,
and as with other ducks, the pair bonds dissolve upon the start
of incubation, and males leave the breeding area to gather in
preferred diet of the Gadwall is the invasive, exotic submergent,
Eurasian Water Milfoil. Gadwalls, especially when they are young,
also eat aquatic invertebrates and the occasional small fish.
late nester, the female Gadwall picks the nest site, which is
usually near water and surrounded by dense weeds or grass. The
nest itself is on the ground, made of grasses and weeds and lined
with down. The female lays 8 to 10 eggs, which she incubates
for 24 to 27 days. Shortly after hatching, the young leave the
nest and can swim and find their own food. The female remains
with the young until they fledge at about ten weeks of age.
are short-distance migrants, most wintering north of the tropics.
Many do not migrate at all, and they can be found year round
in both western and eastern Washington. Most pairs arrive on
the breeding grounds in early April. Fall migration lasts from
late August to October and peaks in September.
Gadwall was traditionally a duck of the Midwestern prairies.
The conversion of the coniferous landscape to a more open one
has helped create habitats more inviting to Gadwalls, as has
the spread of Eurasian Water Milfoil into urban lakes. The first
Gadwall nests in Washington were reported in the mid-1960s. Range-wide,
the Gadwall population fluctuates greatly, but it continues to
expand its range and does not appear to be in decline overall.