The Mute Swan is.

Mute-A person or animal without the power of speech

Sentence:The swan was mute.

The Mute Swan (Cygnus olor) is not altogether silent as the name suggests. It is called this because it does not emit sounds in flight, whilst all other swans communicate in the air. On the water the Mute Swan is far from mute and will squawk louder than most.

mute swan

Well, first the colour. Black swans are ... well... black with a bright red beak and mute swans are white with a black band above the beak and the beak is a orange melting into a red near the tip. Second, mute swans tend to be much quieter than other swans. Mute swans are also one of the heaviest flying birds. Unlike black swans they tend to also be more territorial.