Ducks primarily eat aquatic plants, but they are omnivorous and also eat insects, crustaceans, mollusks, frogs and small fish. Ducks forage for their food and eat whatever is available, although vegetation makes up the core portion of their diet.
Ducks consume all parts of aquatic plants, including the stems, flowers and seeds. Some species even eat microscopic aquatic plants, such as plankton. Furthermore, ducks enjoy land plants and grains, such as rice or barley. Although bread and popcorn are often fed to urban ducks, those foods are not particularly healthy for them. Better alternatives include cracked corn and shredded lettuce.