The comb-duck is often called, even by Europeans, by its best known native name of Nukta or Nukwa, and the practice is one to be commended, as in all cases where a bird is of a type of its own and unfamiliar to Europeans. Although to some extent intermediate between ducks and geese, the nukta would never have been called a black-backed " goose " were the male no bigger than the female, since she is obviously a duck; he, however, is quite as big as an ordinary wild goose, weighing between five and six pounds, while the female is only about three.
In plumage, however, they are much alike, only the female is far less richly glossed with purple and green on the black upper parts, has the sides dirty drab instead of pure delicate grey, and never displays the yellow patch under the sides of tail, and the yellow streak along the head, which the male has when in the height of breeding condition. At this time his black comb is a couple of inches high, but shrinks down to less than half in the off-season ; the female never has one, nor the young male, till he gets his full colour. In immature plumage the birds are brown, not black, but at all stages the combination of white belly with dark under-surface of wings is distinctive of the nukta among our large ducks.
The amount of black speckling on the white head varies a great deal individually; the whitest-headed bird I ever saw was a young male, and he had black on the flanks instead of grey, and was thus like the male South American nukta, which seems to me, therefore, hardly distinct from ours. The African one is now admitted to be the same as the Indian ; no other species is known.
The comb-duck is generally distributed over India, Burma, and Ceylon in suitable localities, such localities being open land provided with plenty of reedy marshes, and scattered large trees; treeless country the bird dislikes, as it is a perching duck and roosts and breeds in the trees ; nor does it care, on the other hand, about actual forest. It seldom frequents rivers, but may be found on lakes, and in some localities even on small ponds. It will thus be seen that its choice of localities is very different from that of the geese, while it is not sociable like them, being very rarely found in flocks of more than a dozen or so, and commonly in pairs. It associates with no other duck but the ruddy sheldrake, and that not often, as the two birds affect different places; and unless it happens to be in such company, is not so wary as one would expect a large waterfowl to be. Most of its time is passed in the water, though it walks as well on land as a goose, and although it feeds freely on rice and land and water herbage, it also partakes of water-snails, insects, &c, like a typical duck. The brown young birds are good eating, but the adults, though not ill-flavoured, are inclined to be hard; they should be cooked and served like geese. On the water the bird sits high with the stern raised, like a goose, but both there and on land the neck is carried in a graceful curve, and when courting the male arches his neck and bends down his head, slightly expanding his wings after the fashion of a swan, only much less. The comb-duck swims well, and dives vigorously if pressed ; in flight it is intermediate in style between a duck and a goose; the male, conspicuous by his size and comb, acts as the leader. It flies and feeds by day, retiring to the trees at night ; it is usually very silent, but the note when heard is variously described, sometimes as loud and goose-like, sometimes as a low guttural quack, or, in the case of the male, as a grating sound; probably only the female has the loud call.
The pair seem much attached, and the male accompanies the female in her search of a nesting-site in the trees ; such a site is a hole, or the place where several large branches diverge; an old nest of another large bird has been used, and even a hole in a bank ; and the nest has even been said to be sometimes placed on the ground among rushes by the water. The eggs are of an unusually polished appearance for a duck's, and yellowish-white ; about a dozen are laid, some time between June and September. The ducklings in down are brown and white above and white below.
The nukta is as well off for names as might be expected; in Telugu it is Jutu chilluwa, in Canarese Bod sarle haki, and in Uriya Nakihansa; Neerkoli is the name in Coimbatore, and Tau-bai in Burma, though the Karens call it Bowkbang.