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.