The gadwall (Mareca strepera) is among the most plain-looking of American ducks. The male appears gray overall, an impression created by white feathers barred with black. The scapular feathers have a reddish-brown cast. Probably the most striking feature of the male gadwall is his solid black rump. His bill is also dark-colored.
The female gadwall is primarily brown with lighter fringes on the feathers. Her bill has more orange coloring than that of her mate. Young gadwalls look basically the same as their mothers, just duller.
Gadwalls fly quickly and directly. It is while airborne that they display their most distinctive field mark—a solid white wing patch on the upper surface of the wing. This patch is sometimes (but not always) visible while swimming, too.
Best Field Marks
- Generally nondescript appearance.
- White speculum on both sexes.
- Black rump on male.
In keeping with generally nondescript appearance of the duck is the fact that it makes very little sound. Gadwalls might quietly repeat tickety-tickety-tickety while feeding or flying, but mostly they are silent until the breeding season. Then the male burps or whistles. The female quacks like a mallard, but with a higher pitch.
Distribution & Occurrence
The gadwall can be found anywhere in Kansas. It arrives in September, spends the winter where temperatures permit, and leaves in May. It prefers shallow, open water with fairly sparse vegetation, such as in marshes, playas, and small ponds.
Although it prefers to nest in the northern Great Plains, the Great Lakes, and the prairie provinces of Canada, the gadwall has been known on rare occasions to nest in Kansas. For this purpose, it requires a shallow marsh with fairly stable water levels, giving it three breeding sites to choose from in our state:
- Cheyenne Bottoms.
- Quivira Wildlife Refuge.
- Slate Creek Marsh.
The gadwall is a shy duck, preferring small, compact groups to large flocks. It does not mind mixing with wigeons and pintails, however.
It feeds during the day, mainly in open water. It dabbles for plant materials fairly close to the surface, particularly underwater weeds and many different grass and sedge seeds. It will sometimes eat insects, snails, crustaceans, and fish. In winter, if the gadwall’s food needs cannot be met in the water, it will try grain fields and sometimes wooded areas.
The courtship display of the breeding gadwall is rather unique, involving the male rearing up and whistling. Once pairs are formed, the ducks bond by bobbing their heads and laying their necks out flat on the surface of the water. Next, they go to find a nesting site, preferably near the area where the female was born.
A gadwall nest may be nothing more than a low spot that the female has dug out, usually well hidden in tall grasses near the water. The female lines the nest with grasses, weeds, and down, and then lays an average of nine white to cream eggs. The male guards her during this process. Once the eggs are laid, however, he leaves to find a safe place to molt.
After 24 to 28 days, the young hatch. They are able to hunt for themselves right away, but the female will guide and protect them until they grow adult feathers.
Attracting gadwalls is more the goal of hunters than of birdwatchers. These ducks are very wary, however, and hard to decoy. Both gadwall and mallard decoys can be used to attract their attention. To convince them to land, hunters may use quiet calls mimicking the sound of contented gadwalls, but sparingly—gadwalls can easily detect when the calls are overdone.
The female gadwall looks almost identical to the female mallard. The most reliable field mark is the color of the patch on the wing. The mallard has an iridescent blue patch, while the gadwall’s wing patch is white.
Female American Wigeon
The American wigeon can present some confusion at first, especially since it also has white on its wing. The location of the white patch is important to note here. When viewed from the top, the American wigeon’s white patch is on the shoulder, while the gadwall’s is on the trailing edge of the wing. If the top of the wing is not visible, another good rule of thumb is to look at the bill. The female American wigeon has a blue-gray bill, while the female gadwall’s bill is more orange overall.
Photos, audio, and more information from Cornell’s All About Birds site.