The cuckoos are a family, Cuculidae, of near passerine birds. The order Cuculiformes, in addition to the cuckoos, also includes the turacos (family Musophagidae, sometimes treated as a separate order, Musophagiformes). Some zoologists have also included the unique Hoatzin in the Cuculiformes, though it is now usually placed in an order of its own, Opisthocomiformes.