Not far removed from these are the Pintailed Ducks (Dafila), which may be recognized at once by the rather long neck, the bill narrow and longer than the head, and above all by the elongation of the middle pair of tail-feathers in the male. Two or three species are now recognized, the commonest and most widely distributed being the common Pintail (D. acuta) of the Northern Hemisphere in general, migrating south in winter to middle America and the West Indies in the New World, and to the Mediterranean countries, India, and the Indo-Malayan Archipelago in the Old World. The sexes are much alike in summer, but in winter they are quite different, the male at this season having the head and upper neck olive-brown, the back of the neck black with a white stripe on each side which is confluent with the white of the breast and lower parts; the back, sides, and flanks marked with wavy lines of black and white, while the scapulars are velvety black edged with whitish, and the speculum is metallic green or bronze purple; the length is from twenty-eight to thirty inches.
The Pintail breeds in North America from the northern United States north-ward, being, for example, the most universally abundant Duck found in North Dakota, where it is evenly distributed throughout the prairie regions in lakes and ponds and sloughs wherever they are of sufficient size. Mr. Bent, who has had much experience among the water fowl of this region, states that the nest of the Pintail is ” placed almost anywhere on dry ground, or sometimes near the edge of a slough or pond, sometimes on the islands in the lakes, but more often on the prairies, and sometimes a half a mile or more from the nearest water. The nest is poorly concealed, and often in plain sight. A deep hollow is scooped out in the ground, which is sparingly lined with bits of straw and stubble, and a scanty lining of down is deposited around the eggs.” The eggs, which are usually from eight to ten in number, are pale olive-green or olive-buff, and measure about two and twenty-five hundredths by one and fifty hundredths inches. The female is described as very solicitous for the safety of her brood,flying around over the head of the intruder or splashing down in the water within a few feet and acting as if wounded, quacking excitedly all the time.
This species is also very common along the Yukon, where it nests usually in the sedge,lining the nest with dry grass, and when both parents leave the eggs they are carefully covered with dry leaves and feathers. As soon as the young are hatched they repair to the small creeks and tributaries of the great river until they can fly, when they go to the vast marshes and feed upon the roots of the horse-tail, and become so fat that they rise from the water with difficulty. By the end of September they have all left for the South. In the Old World the main breeding ground of the Pintail is north of latitude 6o °, although it may come some-what south of this in Siberia, Russia, and northern Germany, and a few still spend the summer in England and Ireland. In the latter places its breeding haunts are the rocky inlets in quiet sloughs and firths, often at a considerable distance from the mainland.
The other species of Pintail are found in the Southern Hemisphere, one of the best known being the Brown Pintail (D. spinicauda) of South America. This handsome Duck, which is much smaller than the one just described, is, according to Hudson, the commonest Duck in the Argentine Republic and unites in the largest flocks. Its nest is built on the ground under the grass or thistles, at a distance from water, and is plentifully lined with down plucked from the breast of the female. In autumn it often visits the pampas in vast numbers to feed upon the seeds of the giant thistle, where it clusters so closely that as many as sixty have been killed at a single shot. The Bahama Pintail (D. bahamensis) is another species which is mainly spread over South America, while a still smaller species (D. Galapagensis) is confined to the Galapagos Archipelago. These last two, together with the Red-billed Duck (D. Erythrorhyncha) of Africa, are by some separated as a distinct genus (Paecilonetta).