More than 100 bird species have been recorded on the Flats, including at least 21 species of waterfowl. The area is important as a breeding and moulting ground to some 500,000 waterfowl.

Aerial surveys indicate that waterfowl breeding populations over the past 30 years have included:

• 20,000-80,000 White-winged and Surf Scoters (Melanitta fuscaand M. perspicillata),
• 50,000-100,000 Scaup (Aythya marillaand A. affinis),
• 20,000-100,000 American Wigeon (Anas americana),
• 10,000-100,000 Northern Pintails (Anas acuta),
• 5,000-40,000 Canvasbacks (Aythya valisineria), and
• 10,000-30,000 Oldsquaw (Clangula hyemalis).

The Flats also support Tundra Swans (Cygnus columbianus), White-fronted Geese (Anser albifrons), three species of Loons (Gavia sp.), and a variety of other waterbirds.

Banding studies have shown these birds to be associated with all four North American Flyways. Waterfowl are more concentrated here than at other locations in the north. Densities of ducks on the Flats are usually around 80 ducks per square km--two to three times higher than in any of the 11 Alaskan waterfowl breeding grounds surveyed annually by the U.S. Fish and Wildlife Service. Some birds breed and moult on the Flats, while others such as Barrow's Goldeneye (Bucephala islandica) do not breed there but come in midsummer from further south to undergo their annual moult.

• Northern Shoveler
• Ring-necked Duck