This beautiful and monogamous bird is usually known as lovely and gentle but it can be tremendously aggressive in defence of its nest.
Its size and impressive hissing make it a formidable adversary for animals as large as a fox.
Mute Swans even attack people who enter their territory during the breeding season as I could experience myself a couple of years ago.
Dutch name : Knobbelzwaan
German name : Höckerschwan
Latin name : Cygnus olor