The largest members of the waterfowl family Anatidae, and are among the largest flying birds. The largest species can reach a length of over 1.5 m (60 inches) and weigh over 15 kg (33 pounds).

Sexes

The geese lack sexually dimorphic plumage.

Southern resident species typically show less sexual dimorphi**, although there are excepti*** like the Paradise Shelduck of New Zealand which is both strikingly sexually dimorphic and where the female's plumage is brighter than that of the male. The plumage of juvenile birds generally resembles that of the female.

The sexes are alike in plumage, but males are generally bigger and heavier than females.

Freshwater/Saltwater

Both fresh water and sea water. Commonly fresh water, such as lakes, ponds, ricers, etc.

Both fresh water and sea water.

Commonly fresh water, such as lakes, ponds, ricers, etc.

Environments

Are generally found in temperate environments, across most of the world except for Antarctica.

The ducks have a co**opolitan distribution occurring across most of the world except for Antarctica.

The swans are generally found in temperate environments.

Migration

Several species are migratory, either wholly or partly so. Most migrate annually. They usually fly in a V-formation.

Some duck species, mainly those breeding in the temperate and Arctic Northern Hemisphere, are migratory; those in the tropics, however, are generally not. Some ducks, particularly in Australia where rainfall is patchy and erratic, are nomadic, seeking out the temporary lakes and pools that form after localised heavy rain.

Several species are migratory, either wholly or partly so.

Behaviour

Males exhibit agonistic behaviour both on and off breeding and nesting grounds. This behavior rarely involves interspecific killing.

Most duck species breed once a year, choosing to do so in favourable conditi*** (spring/summer or wet seas***).

Reach sexual maturity between 4 and 7 years of age. Are aggressively territorial.

Feeding

Geese are primarily herbivores, although they sometimes eat **all insects and fish. Their diet includes green vegetation and grains. The Canada goose eats a variety of grasses when on land.

Diving ducks and sea ducks forage deep underwater. Dabbling ducks feed on the surface of water or on land.

Ducks exploit a variety of food sources such as grasses, aquatic plants, fish, insects, **all amphibians, worms, and **all molluscs.

Swans feed in the water and on land. They are almost entirely herbivorous, although they may eat **all amounts of aquatic animals. In the water food is obtained by up-ending or dabbling, and their diet is composed of the roots, tubers, stems and leaves of aquatic and submerged plants.

Breeding

Geese are monogamous, which means that they live permanently in pairs. However, unlike most other permanently monogamous animals, they are territorial only during the short nesting season.

The ducks are generally monogamous, although these bonds generally last only a single year. Larger species and the more sedentary species tend to have pair-bonds that last numerous years. Mother ducks are very caring and protective of their young, but may abandon some of their ducklings if they are physically stuck in an area they cannot get out of or are not prospering due to genetic defects or sickness brought about by hypothermia, starvation, or disease.

They can form socially monogamous pair bonds from as early as 20 months that last for many years, and in some cases these can last for life. "Divorce" does sometimes occur, particularly following nesting failure.

Lifespan

The lifespan of a goose is usually 10 to 24 years in the wild.

The lifespan of a duck is usually 5 to 10 years in the wild.

The lifespan of the mute swan is often over 10 years, and sometimes over 20, however may survive for less in captivity.

Nesting

Its nest is usually located in an elevated area near water such as streams, lakes, ponds and sometimes on a beaver lodge. Its eggs are laid in a shallow depression lined with plant material and down.

Ducks also tend to make a nest before breeding, and after hatching to lead their ducklings to water.

The nest is on the ground near water and about a metre across. Unlike many other ducks and geese the male helps with the nest c***truction.

Eggs

The female lays from 2–9 eggs with an average of five and both parents protect the nest while the eggs incubate, but the female spends more time at the nest than the male.

Most domestic ducks neglect their eggs and ducklings, and their eggs must be hatched under a broody hen or artificially. Clutch size is 9 on average for American black duck, and 8 – 16 for Muscovy duck.

Average egg size (for the mute swan) is 113×74 mm, weighing 340 g, in a clutch size of 4 to 7, and an incubation period of 34–45 days. Males aid in incubating the eggs.