What is "olor cygnus"

Hooper \Hoop"er\, n. (Zo["o]l.) [So called from its note.] The European whistling, or wild, swan ( Olor cygnus); -- called also hooper swan, whooping swan, and elk.

Swan \Swan\ (sw[o^]n), n. [AS. swan; akin to D. zwaan, OHG. swan, G. schwan, Icel. svanr, Sw. svan, Dan. svane; and perhaps to E. sound something audible.]

1. (Zo["o]l.) Any one of numerous species of large aquatic birds belonging to Cygnus, Olor, and allied genera of the subfamily Cygnin[ae]. They have a large and strong beak and a long neck, and are noted for their graceful movements when swimming. Most of the northern species are white. In literature the swan was fabled to sing a melodious song, especially at the time of its death.

   Note: 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 ( O. Columbianus), and the trumpeter swan ( O. 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.

2. Fig.: An appellation for a sweet singer, or a poet noted for grace and melody; as Shakespeare is called the swan of Avon.

3. (Astron.) The constellation Cygnus.

   Swan goose (Zo["o]l.), a bird of India ( Cygnopsis cygnoides) resembling both the swan and the goose.

   Swan shot, a large size of shot used in fowling.