Anseriformes is the order of aquatic birds that includes ducks, geese, swans, magpie geese and screamers.

These birds are sometimes called waterfowl.

About 160 species of anseriformes are alive today.

Ducks, geese and swans belong to the family Anatidae.

Anatidae make up the vast majority of Anseriform species.

The magpie goose, Anseranas semipalmata, is the only member of the family Anseranatidae. It lives in Australia and New Guinea.

Canvasback DuckScreamers belong to the family Anhimidae.

There are three species of screamer, which live in South America.

Anseriformes live all over the Earth, except for Antarctica.

They tend to be medium to large in size, ranging from about 1 to 5 feet long. They can weigh as little as about ½ or as much as about 40 pounds.

All of the anseriformes have webbed feet, which allow them to swim efficiently.

They have relatively long necks, which help them to reach food under water.

Their bodies tend to be broad, which makes it easy for them to float.

The diet of anseriformes includes plant matter, such as leaves, stems, roots, seeds and flowers, as well as plankton, mollusks, crustaceans and fish.

Most anseriformes have broad flat bills with plates called lamellae, which filter food particles out of the water.

An anseriform has a modified tongue that behaves like a suction pump, sucking water into the front of the bill. After the water has been filtered, it passes out though the bill's sides and back.

Anseriformes often form flocks. These can be small collections of a few individuals or large groups of several thousand individuals.

The majority of the anseriformes are very strong flyers. There are a small number of flightless species.

Canada Geese, photo by Don DeBoldSome anseriformes migrate long distances.

The Canada goose is famous for its long migration, from  Canada, Alaska and the northern continental United States to the southern continental United States and Mexico.

Anseriformes are precocial. This means that they can move about by themselves as soon as they hatch. When it leaves the egg, an anseriform already has its eyes open and is covered in down. It is soon able to forage for its own food.

Animals that cannot move around by themselves as soon as they hatch or are born are altricial.

The earliest anseriform that we know of lived about 65 million years ago.

Humans hunt many different species of anseriformes.

Some anseriformes have been domesticated for food, for their eggs and for their feathers.