Chauna

Chauna is a genus of large waterbirds in the family Anhimidae, within the order Anseriformes. They are commonly known as screamers. The two extant species are Chauna torquata, the southern screamer, and Chauna chavaria, the northern screamer. Screamers are among the most primitive living waterfowl, with long necks, heavy bodies, and relatively small wings. They have lobed feet adapted for both walking on land and swimming, and they can fly, though they typically prefer to move by walking and running on open terrain.

Distribution and habitat

Northern screamers (C. chavaria) inhabit wetlands in northern South America, including parts of the Amazon basin. Southern screamers (C. torquata) occur across a broader swath of southern and central South America, inhabiting lakes, marshes, and riverine habitats. They are often found in grassy or reedy wetlands adjacent to open water and are well adapted to seasonal changes in water levels.

Behavior and ecology

Chauna species are primarily herbivorous, feeding on grasses, aquatic plants, seeds, and occasionally small invertebrates. They are social birds that may form pairs or small groups, especially outside the breeding season. Their vocalizations are loud and distinctive, which has led to their common name.

Reproduction

Both species nest near water, constructing ground-level nests close to the shoreline. Clutch size is variable, and both parents participate in incubation and chick rearing. The precocial young are capable of swimming soon after hatching.

Conservation

The IUCN generally lists both species as Least Concern, though local populations can be affected by wetland loss and habitat degradation. Chauna remains of interest to researchers for its evolutionary position among waterfowl.