The Mute Swan (Cygnus olor): Body length 140-160 cm, wingspan 200-240 cm. It is a huge bird with white plumage and very long neck with small head. The tail is comparative long and pointed. It has an orange bill with a black knob on the forehead. Sexes are similar, the male has a larger bill-knob than female and usually during breeding they seem larger than females with deep orange bill. Juveniles are grey-brown with first dark grey bill and then pinkish-grey bill without a knob(Svensson, Mullarney and Zetterstrom, 2009).
Mute Swan breeds on freshwater lakes and along coasts. It is not a shy bird and sometimes it can be aggressive, male Swans often have territorial fights with wing-splashing rushes. Mute Swans keep their neck either straight or smoothly bent in S-shape when they are swimming. The threat posture is with wings raised like sails and head lowered over back (Svensson, Mullarney and Zetterstrom, 2009).
They mainly feed on aquatic plants.
Svensson, L., Mullarney, and K. and Zetterstrom, D., 2009. Collins Bird Guide. 2nd ed. Translated by D. Christie and L. Svensson. United Kingdom: HarperCollins Publishers Ltd.