Howard...
You might find the following site interesting
http://www.royal.gov.uk/RoyalEventsandCeremonies/SwanUpping/SwanUpping.aspx
From the site...."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."
I wonder what swan tastes like, a bit duck or goose or is it completely different.