Geese Ducks and Swans: Anatidae - Behavior And Reproduction, Mute Swan (cygnus Olor): Species Accounts, Canada Goose (branta Canadensis): Species Accounts - PHYSICAL CHARACTERISTICS, GEOGRAPHIC RANGE, HABITAT, DIET, GEESE DUCKS SWANS AND PEOPLE, CONSERVAT

Anatids (members of the family Anatidae) are medium to extra-large birds with stocky bodies, webbed feet, and a flat bill. Coloring varies but is primarily brown with white, black, and metallic green accents. The smallest species stands 13 inches (33 centimeters) and weighs no more than 0.5 pounds (0.2 kilograms) while the largest grows up to 6 feet (1.8 meters) in length and weighs up to 49 pounds (22.5 kilograms).

Found on all continents except Antarctica.

Anatids need water. Some require fast-flowing streams; others prefer rainforests, tundra, or even the lava fields of volcanoes. Marshland is another common habitat for these birds.

Despite the fact that most geese, ducks, and swans require water bodies for survival, not all species eat aquatic food. Some species are vegetarian and eat primarily seeds, roots, leaves, and stems. Others eat insects, and still others thrive almost exclusively on aquatic invertebrates (water animals without backbones). Some anatids favor plankton and algae (AL-jee).

Anatids and humans have a long history of interaction. Humans have domesticated (tamed) a number of species and have hunted waterfowl almost since the beginning of humankind. Waterfowl hunting is a huge source of revenue in the United States, with outdoor stores selling millions of dollars worth of hunting gear. Also, waterfowl play an important role in keeping the balance of wetland ecosystems.

Six species are Extinct, died out. Four are Critically Endangered, facing an extremely high risk of extinction; nine are Endangered, facing a very high risk of extinction; and twelve species are listed as Vulnerable, facing a high risk of extinction. The greatest threats to these birds are overhunting and wetland drainage. When wetlands are drained, waterfowl can no longer breed there. Pollution from industry also threatens birds in rivers and streams.