The southern screamer (Chauna torquata) is a species of bird in family Anhimidae of the waterfowl order Anseriformes. It is found in Argentina, Bolivia, Brazil, Paraguay, Peru, and Uruguay. Taxonomy and systematics The southern screamer shares genus Chauna with the northern screamer (C. chavaria). One other species, the horned screamer (Anhima cornuta) is also in family Anhimidae. The southern screamer is monotypic. Description The southern screamer is one of the largest birds of southern South America at long and weighing about . Their flat wing measures , their tail , and their culmen . They are stout bodied with a disproportionately small head and a "chicken-like" grayish brown bill. The sexes have the same plumage. Their head and upperparts are gray with a velvety black "collar" around the base of the neck. Their wings and tail are dusky and the wing has two sharp spurs at its manus. The front of their neck, their breast, and their sides are pale gray faintly mottled and streaked with white. Their belly is unmarked pale gray or white. Their legs and feet are rosy. Distribution and habitat The southern screamer is found from the eastern half of Boliva south into Venezuela as far as Buenos Aires Province and east through Paraguay into southwestern Brazil and Uruguay. It has also been documented as a vagrant in southeastern Peru. It inhabits tropical and subtropical wetlands including lakes, marshes, and flooded meadows with scattered trees. Behavior Movement The southern screamer is generally considered to be non-migratory. However, seasonal changes in the numbers present in coastal and inland parts of Brazil's Rio Grande do Sul suggest local movements between them. Locomotion The southern screamer is a good swimmer but prefers to move on the ground. It is an excellent flier and soarer. Feeding The southern screamer feeds on the leaves, stems, and seeds of aquatic plants and also on some crops. They usually graze like geese but have been seen digging for food. Flocks of up to about 100 forage together in the non-breeding season. Breeding The southern screamer forms long-term pair bonds that in some cases last for life. Males and females court with mutual preening and duet calling. They build a large nest of sticks and reeds near shallow water and often nest in about the same location for several years. The typical clutch size is three to five eggs but can be up to