Counting swans

Swan Upping, the annual census of the British Queen's swans, has taken place for nearly 900 years on the Thames River. Not just idle swan counting, the census plays an important role if the conservation of the mute swan.

David Barber, the Queen's Swan Marker, lifts a swan ashore during the annual Swan Upping census along the river Thames, at Staines-on-Thames, southern England, July 20, 2015. Young cygnets are counted and swans and cygnets are assessed for signs of injury or disease during the ceremony.

The five-day census of the swan population dates back to the twelfth century when the Crown claimed ownership of all mute swans. Today, the Crown retains the right to ownership of all unmarked mute swans in open water, but The Queen only exercises her ownership on certain stretches of the River Thames and its surrounding tributaries.

Swan Upping

Swans and cygnets are rounded up to be weighed and tagged during the annual Swan Upping census on July 18, 2016 on the River Thames, South West London.

A week long exercise where unmarked mute swans are now counted - rather than eaten - is a tradition exercised by the British Crown for nearly 900 years, near Shepperton, Southern England.

Swan Upping

Swans and cygnets are rounded up to be weighed and tagged during the annual Swan Upping census on July 18, 2016 on the River Thames, South West London.

Swan Upping

A Mute Swan is carried to be weighed during the annual Swan Upping census on July 18, 2016 on the River Thames, South West London.

Swan Upping

Crew sail in six traditional rowing skiffs in a week long exercise near Shepperton, Southern England, July 18, 2016.

Swan Upping

A swan is examined during Swan Upping at Sunbury, Southern England, July 18, 2016.

Swan Upping

A Mute Swan and cygnets make their way along the River Thames during the annual Swan Upping census on July 18, 2016 on the River Thames, South West London.

Swan Upping

Neave Gilbert looks at a swan as it is placed on the floor under a treee during the annual Swan Upping census on July 18, 2016 on the River Thames, South West London.

Schools are invited to meet the Swan Uppers along the river to encourage an appreciation of wildlife.

Swan Upping

A cygnet, or young swan, is restrained whilst being examined during Swan Upping, the annual census of the swan population on the River Thames, in a week long exercise where unmarked mute swans are now counted - rather than eaten - in a tradition exercised by the British Crown for nearly 900 years, near Shepperton, Southern England, July 18, 2016.

Swan Upping

A young cygnet is carried after being weighed during the annual Swan Upping census on July 18, 2016 on the River Thames.

Swan Upping

Swan uppers wait to process through a lock during the annual Swan Upping census on July 18, 2016 on the River Thames.

Swan Upping

The Sovereign's Swan Marker David Barber checks a cygnet during the annual Swan Upping census on July 18, 2016 on the River Thames.

Swan Upping

David Barber, The Queen's Swan Marker, prepares to set off for Swan Upping at Sunbury, Southern England, July 18, 2016.It takes five days for people to carry out the census between Sunbury, near London, and Abingdon, near Oxford.

Swan Upping

A swan and a cygnet are tagged during the annual Swan Upping census at Staines-on-Thames, southern England, July 20, 2015.

Cygnets are individually tagged to assist in protecting the young birds.

Swan Upping

A cygnet, or young swan, is placed in a boat during Swan Upping near Shepperton, Southern England, July 18, 2016.

Swan Upping

Swan Uppers return swans and cygnets to the water during the census at Staines-on-Thames, southern England, July 20, 2015.