Swan Upping
Each year a group of herdsmen, including The Queen鈥檚 Swan Marker dressed in a red costume, and Swan Wardens of the Worshipful Company鈥檚 of Dyers and Vintners head up the River Thames in six rowing boats from Sunbury to Abingdon marking swans along the way according to their ownership. In a tradition dating back to Edward IV鈥檚 reign, when he sold the swans for money, they are captured to determine their ownership by the marks on their beaks and then their offspring are marked accordingly. Swans belonging to Dyer鈥檚 get one nick in their beaks, the Vintners two notches and the Queen鈥檚 remain unmarked. You can watch the action from the towpaths along the river course.
http://woodlands-junior.kent.sch.uk/customs/curious/index.htm#strawbear