The Bahama Duck, as it is commonly called, though it is very doubtful whether it really occurs in the Bahama Islands, is found throughout South America from British Guiana to Patagonia; and Burmeister says that it is spread over the whole of Brazil, and that it is nearly the commonest species of Duck in that country. On the pampas of Buenos Ayres this Duck is not a common bird. It is usually seen in pairs, or, on rare occasions, three or four together. 352. MARECA SIBILATRIX (Poepp.). (CHILOE WIGEON.) +Anas chiloënsis+, _Burm. La-Plata Reise_, ii. p. 517 (Mendoza). +Mareca chiloensis+, _Scl. et Salv. P. Z. S._ 1869, p. 635 (Buenos Ayres); _iid. Nomencl._ p. 130. +Mareca sibilatrix+, _Scl. et Salv. P. Z. S._ 1876, p. 395; _Durnford, Ibis_, 1877, p. 41 (Chupat), p. 192 (Buenos Ayres), et 1878, p. 401 (Central Patagonia); _Barrows, Auk_, 1884, p. 274 (Bahia Blanca). _Description._--Above black, on the neck barred across with white; feathers of the back and scapularies margined with white; head above and cheeks pure white; nape and back of the neck shining greenish purple; wings brown, lesser wing-coverts white; secondaries velvety black, white at the base: beneath white, throat and fore neck blackish; upper breast black, with narrow white cross bands; flanks stained with rusty rufous; bill and feet black: whole length 20·0 inches, wing 10·3, tail 4·3. _Female_ similar, but not so bright in colour. _Hab._ Paraguay, Argentina, Chili, and Patagonia. The Chiloe Wigeon, as this Duck has been usually called since its introduction and acclimatization in England, is the only species of the genus found in South America, and is most abundant on the pampas, where it is called by the country people _Pato picaso_ or _Pato overo_ (piebald duck), or _Chiriví_ from its cry. It is a very handsome bird; the upper plumage variegated with black, white, and grey; forehead, speculum, and under surface white; head and neck dark glossy green. It is resident, and is usually seen in small flocks of from a dozen to twenty birds, but sometimes as many as one or two hundred congregate together. They are wary and loquacious, strong on the wing, and frequently engage in a peculiar kind of aerial pastime. A small flock will rise to a vast height, often until they seem mere specks on the sky, or disappear from sight altogether; and at that great altitude they continue hovering or flying, sometimes keeping very nearly in the same place for an hour or more, alternately separating and closing, and every time they close they slap each other on the wing so smartly that the sound may be heard distinctly even when the birds are no longer visible. While flying or swimming about they constantly utter their far-sounding cry--three or four long, clear, whistling notes, followed by another uttered with great emphasis and concluding with a kind of flourish.