Swan Upping became important back in the Middle Ages in Britain. Back then, not only was the mute swan a valuable commodity and regularly traded between noblemen, but swan owners were legally bound by the Crown to mark their swans with nicks in their beaks. This activity took place annually in a ceremony called “swan upping”. Although now largely symbolic, the event still takes place today on the Monday of the third week in July, and serves to monitoring the condition and number of swans on the Thames. The year’s new cygnets can be marked when they are reasonably well grown but cannot yet fly. March 2018.