Swan
Swan (swon) , noun
[Anglo-Saxon swan; akin to Dutch zwaan, Old High German swan, German schwan, Icelandic svanr, Swedish svan, Danish svane; and perhaps to English sound something audible.]
The European white, or mute, swan (Cygnus gibbus), which is most commonly domesticated, bends its neck in an S-shaped curve. The whistling, or trumpeting, swans of the genus Olor do not bend the neck in an S-shaped curve, and are noted for their loud and sonorous cry, due to complex convolutions of the windpipe. To this genus belong the European whooper, or whistling swan (Olor cygnus), the American whistling swan (Olor Columbianus), and the trumpeter swan (Olor buccinator). The Australian black swan (Chenopis atrata) is dull black with white on the wings, and has the bill carmine, crossed with a white band. It is a very graceful species and is often domesticated. The South American black-necked swan (Sthenelides melancorypha) is a very beautiful and graceful species, entirely white, except the head and neck, which are dark velvety seal-brown. Its bill has a double bright rose-colored knob.