Ducks are identifiable by their broad, flat bill and short legs while geese are larger than ducks, have shorter bills and longer necks. Ducks and geese also have different social structures, which contributes to their identifications.
Both ducks and geese belong to the same biological family for waterfowl called Anatidae, but they belong in different subfamilies and genera. Ducks belong to eight subfamilies in the Anatidae family. As a general rule, ducks are smaller and stouter than geese with long, broad bills. These bills evolved for scooping food into the ducks' mouths in water or on land, with a serrated tip to strain out the water. Socially, ducks mate only for a season until the eggs are laid and incubated. After hatching, the males of the species leave the females to raise the ducklings. Also, male ducks often have brightly colored plumage that distinguishes them from their female counterparts.
Geese belong to four subfamilies in the Anatidae family. They tend to be larger than ducks with shorter bills, perfect for a diet of grazing on short grasses. Socially, geese mate for life, which cuts down on courtship rituals. Geese have strong family bonds that follow through migration and many seasons.