The Southern Screamer is the southernmost member of one of the most distinctive families of neotropical birds, the screamers (Anhimidae). It is also one of the largest birds found in its range and is easily identifiable by its large size, disproportionately small head, and predominantly gray plumage. Other distinctive features include two bony wing spurs, a lack of feather tracks, and incredibly light bones. The Southern Screamer is common in a variety of marshy and agricultural habitats from Bolivia and southern Brazil south to central Argentina. In Argentina it is locally known to as 'chaja,' in reference to its double-noted trumpeting call, an extraordinarily loud vocalization than can carry for long distances.