From Wikipedia, the free encyclopedia
Swans are birds of the family Anatidae within the genus Cygnus. The swans' close relatives include the geese and ducks. ... Swans usually mate for life, though "divorce" does sometimes occur, particularly following nesting failure, and if a mate dies, the remaining swan will take up with another. The number of eggs in each clutch ranges from three to eight.
Swans are the largest extant members of the waterfowl family Anatidae, and are among the largest flying birds. The largest species, including the mute swan, trumpeter swan, and whooper swan, can reach a length of over 1.5 m (59 in) and weigh over 15 kg (33 lb). Their wingspans can be over 3.1 m (10 ft). Compared to the closely related geese, they are much larger and have proportionally larger feet and necks. Adults also have a patch of unfeathered skin between the eyes and bill. The sexes are alike in plumage, but males are generally bigger and heavier than females.
The Northern Hemisphere species of swan have pure white plumage but the Southern Hemisphere species are mixed black and white. The Australian black swan (Cygnus atratus) is completely black except for the white flight feathers on its wings; the chicks of black swans are light grey. The South American black-necked swan has a white body with a black neck.
The legs of swans are normally a dark blackish grey colour, except for the two South American species, which have pink legs. Bill colour varies: the four subarctic species have black bills with varying amounts of yellow, and all the others are patterned red and black. Although birds do not have teeth, swans have beaks with serrated edges that look like small jagged 'teeth' as part of their beaks used for catching and eating aquatic plants and algae, but also molluscs, small fish, frogs and worms. The mute swan and black-necked swan have lumps at the base of their bills on the upper mandible.
Swans feed in the water and on land. They are almost entirely herbivorous, although they may eat small 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.
Although swans only reach sexual maturity between 4 and 7 years of age, 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. The lifespan of the mute swan is often over 10 years, and sometimes over 20, whereas the black-necked swan survives for less than a decade in captivity. These bonds are maintained year round, even in gregarious and migratory species like the tundra swan, which congregate in large flocks in the wintering grounds.
Swan upping is an annual ceremony in Britain in which mute swans on the River Thames are rounded up, caught, ringed, and then released.
By prerogative right, the British Crown enjoys ownership of all unmarked mute swans in open water. Rights over swans may, however, be granted to a subject by the Crown. (Accordingly they may also be claimed by prescription.) The ownership of swans in a given body of water was commonly granted to landowners up to the 16th century. The only bodies still to exercise such rights are two Livery Companies of the City of London. Thus the ownership of swans in the Thames is shared equally among the Crown, the Vintners' Company and the Dyers' Company.
Swan upping is the traditional means by which the swans on the Thames are apportioned among the three proprietors. Its main practical purposes today are to conduct a census of swans and check their health. It occurs annually during the third week of July. Over five days, the Queen's, Vintners' and the Dyers' respective swan uppers row up the river in skiffs. Swans caught by the Queen's swan uppers under the direction of the Swan Marker are left unmarked, except for a ring linked to the database of the British Trust for Ornithology (BTO). Those caught by the Dyers and Vintners are identified as theirs by means of a further ring on the other leg. Originally, rather than being ringed, the swans would be marked on the bill, a practice reflected in the pub name The Swan with Two Necks, a corruption of "The Swan with Two Nicks".
On 20 July 2009, Queen Elizabeth II, as "Seigneur of the Swans," attended the Swan Upping ceremony for the first time in her reign. This was the first time that the monarch had personally watched the ceremony in centuries.