: an official who cuts a mark of ownership on the upper mandible of a swan.

Why is it called swan upping?

The name of the ceremony is thought to originate from the call, "All Up" - a signal for the boats to circle a brood. Private owners of swans developed a complex system of markings, etched into the swans' beaks to identify them as private, and not Crown, property.

Where is the swan upping?

Swan Upping, the annual census of the swan population on the River Thames will take place for three days in July 2021. Swan Upping will commence on Tuesday 20th July from Eton Bridge, Berkshire and will finish at Moulsford on Thames, Oxfordshire on Thursday 22nd July.