The Genus Cygnus contains six or seven (depending on if you count the Bewick's Swan and Tundra Swan as one species or two). The Swans are the largest birds in the Anatidae family of waterfowl, and the largest examples can have a wingspan of up to 10ft.
Swans normally mate for life, although they will find a new mate if their existing partner dies, and sometimes a mating fails.
European adult swans have white feathers, but southern hemisphere swans include the all-black Black Swan and others with mixed black and white feathers. Male and female swans have the same plumage. The young (or cygnets) often have a different grey plumage.
Swans are a rare example of a bird with 'teeth', in this case jagged patches on their beaks which help them grapple with fish.
Swans share some features in common with all members of the Anatidae family. This includes a flattened bill, a broad body to support their powerful flight muscles, webs between their front toes
Britain has one resident swan, the familiar Mute Swan and two winter migrants - the Whooper Swan which comes from Iceland and Bewick's Swan, which migrates from the Russian tundra. Some Whooper Swans breed in Britain in most years.
Order: Anseriformes (Geese, Swans, Ducks)
Family: Anatidae (Geese, Swans, Ducks)
Genus: Cygnus (Swans)
In some classifications the swans are included in the sub-tribe Anserinae, along with the geese of the Genii Anser and Branta.
Number of Species: six or seven (as of November 2014)
British Members of the Genus
Resident Breeding Species
Mute Swan Cygnus Olor
Whooper Swan Cygnus Cygnus
Bewick's Swan Cygnus Columbianus