Ducks, Geese and Swans
Anatidae is the biological family of birds that includes ducks, geese and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica and on most of the world's islands and island groups. These are birds that can swim, float on the water surface, and in some cases dive in at least shallow water. The family contains around 146 species in 40 genera of which 55 species can be found in the United Kingdom. They are generally herbivorous, and are monogamous breeders. A number of species undertake annual migrations. A few species have been domesticated for agriculture, and many others are hunted for food and recreation. Five species have become extinct since 1600, and many more are threatened with extinction.
Description and ecology
The ducks, geese and swans are small to large sized birds that have a general body plan that is broad and elongated. Diving species vary from this in being rounder. Extant species range in size from the Cotton Pygmy Goose, at as little as 26.5 cm (10.5 inches) and 164 grams (5.8 oz), to the Trumpeter Swan, at as much as 183 cm (6 ft) and 17.2 kg (38 lb). The wings are short and pointed, and supported by strong wing muscles that generate rapid beats in flight. They typically have long necks, although this varies in degree between species. The legs are short, strong, are set far to the back of the body (more so in the more aquatic species), and have a leathery feel with a scaly texture. Combined with their body shape this can make some species awkward on land, but they are stronger walkers than other marine and water birds such as grebes or petrels. They have webbed feet. The bills are made of soft keratin with a thin and sensitive layer of skin on top (which has a leathery feel when touched). For most species, the shape of the bill tends to be more flattened to a greater or lesser extent. These contain serrated lamellae which are particularly well defined in the filter-feeding species.
Their feathers are excellent at shedding water due to special oils. Many of the ducks display sexual dimorphism, with the males being more brightly coloured than the females (although the situation is reversed in species like the Paradise Shelduck). The swans, geese and whistling-ducks lack sexually dimorphic plumage. Anatids are vocal birds, producing a range of quacks, honks, squeaks, and trumpeting sounds, depending on species; the female often has a deeper voice than the male.
Anatids are generally herbivorous as adults, feeding on various water-plants, although some species also eat fish, molluscs, or aquatic arthropods. One group, the mergansers, are primarily piscivorous, and have a serrated bill to help them catch fish. In a number of species, the young include a high proportion of invertebrates in their diet, but become purely herbivorous as adults.
The anatids are generally seasonal and monogamous breeders. The level of monogamy varies within the family, many of the smaller ducks only maintain the bond for a single season and find a new partner the following year, whereas the larger swans, geese and some of the more territorial ducks maintain pair bonds over a number of years. Anatidae are remarkable for being one of the few families of birds that possess a penis; most species are adapted for copulation on the water only. They construct simple nests from whatever material is close to hand, often lining them with a layer of down plucked from the mother's breast. In most species, only the female incubates the eggs. The young are precocial, and are able to feed themselves from birth. One aberrant species, the Black-headed Duck, is an obligate brood parasite, laying its eggs in the nests of gulls and coots. While this species never raises its own young, a number of other ducks will occasionally lay eggs in the nests of conspecifics (members of the same species) in addition to raising their own broods.
Species that live in the United Kingdom
There are 36 Species of ducks that live in the United Kingdom and below are the links to them all. Click below to find out what Species can be Found.
There are 11 species of Goose that can be Found in the United Kingdom
There are 3 species of swan in the United Kingdom
There are 4 species of toothbilled ducks That can be found in the United Kingdom