(Science: ornithology) a curious south American bird (Anhima, or Palamedea, cornuta), often domesticated by the natives and kept with poultry, which it defends against birds of prey. It has a long, slender, hornlike ornament on its head, and two sharp spurs on each wing. Although its beak, feet, and legs resemble those of gallinaceous birds, it is related in anatomical characters to the ducks and geese (Anseres). Called also horned screamer. The name is sometimes applied also to the chaja. See Chaja, and screamer.