Apart from the Channel-billed Cuckoo's large size, its massive pale, down-curved bill, grey plumage (darker on the back and wings) and long barred tail make it difficult to confuse it with any other bird. In flight the long tail and long wings give the bird a crucifix-shaped (cross-shaped) silhouette. Young Channel-billed Cuckoos have more mottled buff, brown and grey plumage. Although they are not nocturnal birds (night birds) in the strict sense, Channel-billed Cuckoos are notorious for calling all night long during the breeding season. This species is sometimes known as the Storm-bird or Stormbird.