They are strong swimmers with medium to large bodies. They have historically been an important food source, and continue to be hunted as game, or raised as poultry for meat and eggs. The domestic duck is sometimes kept as a pet.
Some definitions of the term 'waterfowl' include the saltwater shorebirds or waders, gulls, pelicans, and herons, as well as seabirds such as the albatross, but 'fowl' especially refers to birds used by humans for game.
See also 
|Wikimedia Commons has media related to: Waterfowl|
|Look up waterfowl in Wiktionary, the free dictionary.|
- Flyways.us - U.S. Fish & Wildlife Service, Flyway Councils, waterfowl hunting management in North America