With males averaging about 26 pounds, mute swans are the second largest waterfowl species after the Trumpeter Swan. Mute swans can easily be distinguished from other swans by their curved neck and orange, black-knobbed bill. Mute swans are not actually mute; they are less vocal than other noisy swans. The most familiar sound associated with Mute Swan is the vibrant throbbing of the wings in flight. This sound is unique to the species and may be heard as far away as 1/2 to 1 mile away.