[338.] CYGNUS NIGRICOLLIS, Gm.
(BLACK-NECKED SWAN.)
[Plate XVIII.]
Cygnus nigricollis, Burm. La-Plata Reise, ii. p. 512 (Paraná); Scl. et Salv. Nomencl. p. 129; iid. P. Z. S. 1876, p. 370; Durnford, Ibis, 1877, p. 191 (Buenos Ayres), et 1878, p. 400 (Centr. [Patagonia]); Gibson, Ibis, 1880, p. 33 (Buenos Ayres); Barrows, Auk, 1884, p. 273 (Entrerios).
Description.—White; head and neck black; postocular streak and chin white; lores naked; bill plumbeous; cere red; feet pale carneous: whole length 48·0 inches, wing 17·5, tail 5·5. Female similar.
Hab. Argentina, Chili, and Patagonia.
To my perhaps partial mind this species is preeminent for beauty among the Swans, although it is considerably smaller than the bird of the Old World, and does not, it must be admitted, comport itself so majestically. In questions of this kind it is natural for every one to be somewhat biassed in favour of the things of his own country; but it will be readily admitted by all, I think, that the black-necked bird is one of three species greatly surpassing all others of this genus in beauty—the other two being, of course, the domesticated Swan of Europe and the Australian Black Swan (perhaps the most graceful bird on the globe).
This Swan is very abundant on the pampas of Buenos Ayres and in Patagonia, and ranges south to the Magellan Straits and the Falklands. As a rule they are seen in small flocks, but sometimes as many as two or three hundred congregate together. They are heavy birds and rise with difficulty, and fly rapidly and with great violence, like all heavy-bodied short-winged species; but in no other very large bird with which I am acquainted do the wings produce so loud a rushing sound. In quiet places the beating of their wings can be heard distinctly when the birds are no longer in sight, although, owing to their large size, the eye can follow them very far. Gauchos sometimes capture them by suddenly charging down the wind upon them, uttering loud shouts which greatly terrify the birds, and when they attempt to rise with the wind they only flap along the ground and are easily knocked over. A Gaucho of my acquaintance one day caught three out of a flock of six in this way; but a very strong wind favoured him, and the birds were at some distance from the water, and allowed him to come near before making the sudden charge. As a rule, they are seen on the water, and when on land they keep very close to the margin.
According to Mr. Gibson, who has observed their breeding-habits, they begin to nest in July—just after the winter solstice. The nest is always placed among thick rushes growing in deep water, and the Swan invariably swims to and from her nest. It is built up from the bottom of the swamp, sometimes through four or five feet of water, and rises a foot and a half above the surface. The top of the nest measures about two feet across, with a slight hollow for the eggs, which are cream-coloured and have a smooth glossy shell. The number varies from three to five, and on one occasion six were found. Mr. Gibson has seen the parent bird swimming from the nest with the young on her back.