mute swan

 

So called because it is not very vocal (though not entirely mute).

mute swan (plural mute swans)

1. A species of white plumaged swan, Cygnus olor, having a distinctive orange bill with a black tip, native to Eurasia and widely introduced elsewhere as an ornamental waterbird.

•   mute swan on Wikipedia.Wikipedia
•   Cygnus olor on Wikispecies.Wikispecies