Ducks, swans and geese | Anatidae

Eenden, ganzen en zwanen | Patos, gansos y cisnes | Ducks, swans and geese

In this guide the family numbers 39 species in twenty genera. The length of the neck decides how a species reaches its food: grazing on short waterside growth, sieving at the surface, upending with the tail in the air, or diving to the bottom — on a single Andean lake or coastal lagoon these methods often occur side by side. Besides the true ducks the family holds goose-like forms with long legs and an upright stance, such as the Andean Goose that grazes the boggy grasslands of the puna and the Orinoco Goose of riverbanks in the lowlands at the foot of the Andes, as well as whistling ducks that are active mainly at dusk and by night and take their name from the clear flight call, and stiff-tails that lie low in the water and display with the tail cocked. Peculiar to the Andes is the Torrent Duck, which swims upstream in fast mountain rivers and dives among the boulders of the rapids for insect larvae. Unlike the ducks of the northern temperate zone, in many resident species here the sexes differ little or not at all and there is no eclipse plumage; the distinctions then lie in bill and eye colour, in the size of a knob, and in the pattern of the speculum. Nests are a scrape lined with the female's own breast down among waterside vegetation, a tree hole or a rock crevice; in most species the female incubates alone and leads the downy young, while in whistling ducks both parents share incubation. The young feed themselves from the first day.