LONDON, ENGLAND - JULY 20:  'Swan Uppers' make their way through a gaggle of swans on the River Thames on July 20, 2015 in London, England. The historic Swan Upping ceremony dates back to the 12th century, to when the Crown claimed ownership of all Mute Swans and they were eaten at banquets and feasts. The Sovereign's Swan Marker, David Barber, counts the number of young cygnets on the river each year and ensures that the swan population is maintained. The swans and young cygnets are also assessed for any signs of injury or disease.  (Photo by Peter Macdiarmid/Getty Images)