Swan-uppingThe capture and marking of Mute Swans Cygnus olor. Traditionally swan-upping is carried out on the Thames by two of the City of London 'Livery Companies', namely the Vintners' and the Dyers' Companies, the birds having 'swan marks' cut into their bills.
Search Bird Dictionary
From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver