SWAN, in ornithology, any individual of the genus Cygnus. The swans form a sharply-defined group; the body is elon gated, the neck very long, head moderate; beak about as long as head; legs short, and placed far back. On the under sur face the plumage is thick and fur like; on the upper side the feathers are broad, but both above and below the body is thickly covered with down. Their short legs render the movements on land awk ward and ungainly, but in the water these birds are graceful to a proverb. Their food consists of vegetable substances and weeds, their long necks enabling them to dip below the surface and to reach their food at considerable depths. Swans breed in high latitudes, but the domesticated species, Cygnus olor, the mute swan, breeds on eyots and the shores of lakes, making a very large nest on land, in which five or six greenish eggs are de posited. The young generally are cov ered with a gray down till the age of two years, when they assume the char acteristic white plumage of the older birds. Three other species visit temper ate Europe: the elk, hooper, whooper, or whistling swan (C. musicus) ; Bewick's
swan (C. bewicki), and the Polish swan (C. inonutabilis), which owes its specific name to the fact that the cygnets are pure white like the parent birds. The mute swan is the largest and most ma jestic of the four, and is easily recognized by the black knob at the base of the bill. There are some other species, chiefly from North America, but the most beautiful the, whole genus is the black-necked swan (C. vigricollis), from South Amer ica; while the most remarkable is the black swan (C. atratus), from Australia, first taken to other countries early in the 17th century. So convinced were the ancients that white plumage was of the essence of a swan, that a "black swan" was a proverbial expression for some thing extremely rare. The stories about the musical voice of the swan appear to have some foundation in fact so far as regards the whooper (C. musicus). In astronomy, the constellation CYGNUS (q. v.). Figuratively applied to a famous poet; thus Shakespeare is called the Swan of Avon, Vergil the Swan of Man tua.