Length is about 20 inches. Plumage is dark brown. Bill and legs are black. Voice usually silent, but utters wide range of high notes when flying or during courtship. Its stiff, backward-pointing crest, along with its peculiar bill, gives the head a hammer shape appearance. Sexes are similar. In flight, it flies like a heron. It has a “comb-claw” but no powder-down. Average weight is between 465g and 500g.