Swan Upping is the annual census of the swan population on stretches of the Thames. 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.
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 Thames and its surrounding tributaries.
This ownership is shared with the Worshipful Company of Vintners and the Worshipful Company of Dyers, who were granted rights of ownership by the Crown in the fifteenth century. Nowadays, of course, the swans are no longer eaten.
In the Swan Upping ceremony, The Queen's Swan Marker, the Royal Swan Uppers and the Swan Uppers of the Vintners' and Dyers' livery companies use six traditional Thames rowing skiffs in their five-day journey up-river.
The Queen's Swan Uppers wear traditional scarlet uniforms and each boat flies appropriate flags and pennants.
When a brood of cygnets is sighted, a cry of "All up!" is given to signal that the boats should get into position. On passing Windsor Castle, the rowers stand to attention in their boat with oars raised and salute "Her Majesty The Queen, Seigneur of the Swans".