This very fine Ibis, called _Mandurria ó curucáu_ by Azara and _Vanduria de Invierno_ (winter Vanduria) in the vernacular, is one of the most interesting winter visitors from Patagonia to the pampas of Buenos Ayres. It is found in Chili, and has even been obtained as far north as Peru. On the east side of the continent it is most abundant (during the cold season) about latitude 37° or 38°. Its summer home and breeding-ground appears to be in the extreme south of the continent, its eggs having been obtained in the Straits of Magellan by Darwin, and recently by Dr. Cunningham, who only says of it that it is a shy and wary bird, that goes in flocks of from four to eight, and has a cry resembling _qua-qua, qua-qua_. But he might just as well have spelt it _quack-quack_, since _qua-qua_ fails to give the faintest idea of the series of hard abrupt notes of extraordinary power the bird utters, usually when on the wing, which sound like blows of a powerful hammer on a metal plate. On the pampas this Ibis appears in May, frequents dry grassy situations, and goes in flocks of a dozen to forty or fifty individuals. They walk rapidly, stooping very much, and probing the ground with their long slender curved beaks, and appear to subsist principally on the larvæ of the large, horned beetle, with which their stomachs are usually found filled. So intent are they on seeking their food that the members of a flock often scatter in all directions and wander quite out of sight of each other; when this happens they occasionally utter loud vehement cries, as if to call their companions, or to inform each other of their whereabouts. Frequently one is seen to lift up its wings as if to fly, and, stretching them up vertically, to remain for fifteen or twenty seconds in this curious attitude. At sunset they all rise up clamouring, and direct their flight to the nearest watercourse, and often on their way thither go through a strange and interesting performance. The flock suddenly precipitates itself downwards with a violence wonderful to see, each bird rushing this way and that as if striving to outvie its fellows in every wild fantastic motion of which they are capable. In this manner they rise and descend again and again, sometimes massed together, then scattered wide apart in all directions. This exercise they keep up for some time, and while it lasts they make the air resound for miles around with their loud percussive screams. In Patagonia I first observed this Ibis roosting on tall trees; and, according to Azara, it possesses the same habit in Paraguay. He says that all the flocks within a circuit of some leagues resort to one spot to sleep, and prefer tall dead trees bordering on the water, and if there is only one suitable tree all the birds crowd on to it, and in the morning scatter, each family or pair flying away to spend the day in its customary feeding-ground.