Gadwall

Anas strepera

(c) Glen Smart, USFWS
  • ANATIDAE
  • Swans, Geese, Ducks
  • Anseriformes
  • Pato ruidoso, Anade riente
  • Canard chapeau
Introduction
The Gadwall is a common dabbling duck found across the northern hemisphere. Unlike many other North American ducks, its numbers have not only remained stable, but have actually increased significantly over the past several decades, due in part to effective land management.
(c) Scott Elowitz
Appearance Description
This medium-sized duck measures about 20 inches in length, and is slightly smaller than a Mallard. At first glance, adult males seem to lack any particular distinguishing characteristics; they are brownish-gray overall, with a sandy brown head. Upon closer scrutiny, the male displays a handsome array of tones, from the steely silver flanks, to the rusty back. In contrast, the rump is black, perhaps the Gadwall’s most distinct field mark at rest. Females are similar to males, but even more understated. In flight, both male and female show a white speculum, or wing patch—the only North American duck species to do so.
Range Map
Courtesy of Kenn Kaufman
Range Distribution
In North America, the Gadwall breeds mainly in the “prairie pothole” region—the grassy wetland at the heart of the Great Plains and Canadian Prairie Provinces. Away from the Great Plains, they breed north as far as Alaska and west to California, south into Texas, east into the Great Lakes region, and locally as far away as coastal New England. Globally, they breed across central Europe into Asia, and winter across Asia and northern Africa. The Gadwall may have the widest global range of any duck species.
 
A legend for the range map to the right can be found here.
Habitat
In winter and migration, the Gadwall can be found in a variety of aquatic habitats, ranging from coastal marshes, to lakes, reservoirs, and ponds. They prefer shallow water. Their breeding habitat consists of open grassy areas with low vegetation for cover, and access to water.
Feeding
The Gadwall feeds mainly upon aquatic plant life and small aquatic invertebrates. Like all dabbling ducks, they feed by tipping steeply forward into shallow water to reach submerged food sources. They are known to dive for food occasionally, and also forage for grains in farm fields.
Reproduction
Gadwall establish pair bonds during fall migration, then remain together until the breeding season. On the breeding grounds, the female builds a cup nest, usually on bare ground in a concealed, grassy area. Nests are lined with leaves, grasses, and twigs, and plucked feathers. Gadwall prefer breeding on islands, which may contribute to a breeding success rate much greater than that of other ducks. They also nest later in the season than most ducks, often choosing fields that have already been mown. The female lays up to 12 eggs, which are incubated for about 26 days. Upon emergence from their shells, the ducklings are able to feed themselves, but remain with the mother hen for up to 10 weeks.
Migration
There are few, if any, non-migratory Gadwall populations. Migration takes place at night. The majority of North American Gadwall cross the Midwest, especially along the Mississippi River corridor, migrating between their prairie breeding grounds and wintering areas around the Gulf Coast. A lesser coastal migration also occurs, so Gadwall are likely to show up just about anywhere in the continental U.S. during migration.
CBC Graph
Graph Legend
Annual Population Indices
  • 5,102,500
  • 3,900,000
  • no current conservation concerns
Population Status Trends
The Gadwall has fared well in North America over recent decades, expanding both its numbers and range significantly. In the 1980s and 1990s, Gadwall populations increased dramatically at the heart of the breeding range, due mainly to improved wetland conditions and favorable land management decisions.
 
An explanation of the Annual Population Indices graph displayed to the right can be found here.
Conservation Issues
The Gadwall benefited greatly from two separate land conservation initiatives in the mid 1980s. The Conservation Reserve Program of 1985 procured over 2 million hectares of land in the prairie pothole region, transforming much of it to habitat favorable for nesting Gadwall. From 1985 to 1995, the U.S. Fish and Wildlife Service’s Waterfowl Habitat Acquisition Plan produced similar results. These land management decisions bolstered Gadwall numbers to record highs, despite their status as a very popular game bird. The Gadwall would further benefit from restoration of the coastal wetlands on their wintering grounds along the Gulf of Mexico.
What You Can Do

Remain aware of local, regional, and federal land management decisions, particularly those that impact our wetlands.

Contact your legislators in support of wise land management initiatives, such as wetland restoration along the Gulf, and implementation of The North American Waterfowl Management Plan.

For actions you can take, including Audubon activities, please visit our resources page.
More Information
Ducks Unlimited maintains important information on many current issues affecting North American waterfowl: http://www.ducks.org/conservation/index.asp
Visit our resources page for more information about this species.
Natural History References
LeSchack, C. R., S. K. McKnight, and G. R. Hepp. 1997. Gadwall (Anas strepera). In The Birds of North America, No. 283 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and the American Ornithologists’ Union, Washington, D.C.
 
Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York, 1996
 
Kortright, Francis H. The Ducks, Geese and Swans of North America. The American Wildlife Institute, Washington D.C., 1943.
Conservation Status References

LeSchack, C. R., S. K. McKnight, and G. R. Hepp. 1997. Gadwall (Anas strepera). In The Birds of North America, No. 283 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and the American Ornithologists’ Union, Washington, D.C. <

Kaufman, Kenn. Lives of North American Birds. Houghton Mifflin Company, New York, 1996
 
Kortright, Francis H. The Ducks, Geese and Swans of North America. The American Wildlife Institute, Washington D.C., 1943.