The Whistling Duck, in its chestnut and fulvous plumage, is a handsome bird and somewhat singular in appearance, especially when seen in a large body on the ground. When out of the water they crowd close together, and when disturbed stand up craning their necks, looking strangely tall on their long blue legs. While thus watching an intruder they are silent, and the sudden ringing chorus of whistling voices into which they burst at the moment of rising has a curious effect.
So extremely social are these Ducks that even when breeding they keep together in large flocks. The nest is made of stems and leaves, on the water among the reeds and aquatic plants; and sometimes large numbers of nests are found close together, as in a gullery. The eggs are pure white, and each bird lays, I believe, ten or twelve, but I am not sure about the exact number; and I have so frequently found from twenty to thirty eggs in a nest that I am pretty sure that it is a common thing for two or three females to occupy one nest.
+Dendrocygna viduata+, _Burm. La-Plata Reise_, ii. p. 515 (Tucuman); _id. P. Z. S._ 1872, p. 367; _Scl. et Salv. P. Z. S._ 1869, p. 160 (Buenos Ayres), et 1876, p. 376; _Durnford, Ibis_, 1878, p. 64 (Buenos Ayres).
_Description._--Face and spot on the throat white; nape, neck in front, middle of abdomen, tail, rump, and wings black; hind neck chestnut; middle of back and scapulars brown, the feathers margined with ochraceous; wing-coverts olivaceous black; flanks banded with black and white; bill and feet black: whole length 17·0 inches, wing 9·0, tail 2·5. _Female_ similar.
This Tree-Duck resembles that last described in size, form, and maroon-red plumage, but is of a darker tint, and may also be easily distinguished, even at a long distance, by its white face contrasted with the velvety black of the head and neck. Compared with _Dendrocygna fulva_ it is a rare species, being usually found in pairs in the Plata district, although sometimes as many as half a dozen are seen together. When taking wing it also whistles, but differently from the allied species, having three long clear whistling notes, not unlike the three-syllabled cry of the Sandpiper, only the notes are more prolonged. Of its breeding-habits I know nothing.