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.
Swan Upping is the annual census of the swan population on stretches of the Thames in the counties of Middlesex, Surrey, Buckinghamshire, Berkshire and Oxfordshire. This historic ceremony dates from the twelfth century, when the Crown claimed ownership of all mute swans. At that time swans were regarded as a delicious dish at banquets and feasts.