Chajá, as it is called in imitation of its cry, inhabits the marshes, lagoons, and level open country abounding in water and succulent grasses of southern Brazil, Paraguay, and La Plata, where according to Mr. W. H. Hudson it is often seen in thousands. “It is,” he says, “partially aquatic in its habits; and in desert places it is usually seen in marshes, wading in the shallow water, and occasionally swimming to feed on the seeds and succulent leaves of water-loving plants.” It also feeds upon the forage plants that have been introduced since the European occupation of the country, being especially fond of clover. Notwithstanding the presence of its powerful wing-spurs it seems to be a very even-tempered and peaceful bird, rarely or never quarreling. Its voice is a marked feature. To quote again from Mr. Hudson, who says on this point : “The voice is very powerful. When disturbed, or when the nest is approached, both birds utter at intervals a loud alarm-cry, resembling in sound the anger-cry of the Peacock, but twice as loud. At other times its voice is exercised in a kind of singing performance, in which male and female join, and which produces the effect of harmony. The male begins, the female takes up her part, and then with marvelous strength and spirit they pour forth a torrent of strangely contrasted sounds, some bassoon-like in their depth and volume, some like drum-beats, and others long, clear, and ringing. It is the loudest animal sound of the pampas, and its jubilant martial character strongly affects the mind in that silent melancholy wilderness.” They are said to sing at all seasons of the year and often at all hours of the night, and when congregated in flocks they often sing in concert.
The nest is a large though light structure of dry rushes, placed among low rushes and water lilies and not infrequently is seen floating away from its moorings. The eggs are usually five, pure white, and about the size of those of the domesticated Goose.
The remaining species (Chauma chavaria), the Derbian Screamer, is a native of Venezuela and Colombia. It is a smaller bird than the others, being about twenty-eight inches in length, with the plumage slaty black, the upper parts glossy and the lower parts paler, the cheeks and throat white, set off sharply from a black collar.