A large, heavy-billed songbird. Highly variable. In the Kai islands and western Lesser Sundas, plumage is uniform blackish-gray; on Sumba, birds are pale gray above with an all-black tail, black face, and white belly; and in the eastern lesser Sundas, darker slaty-gray above with a black face mask. Singles and pairs frequent many habitats including forest, edge, woodland, and savanna, from lowlands into mountains. Large size and very heavy bill of all forms distinguishes them from all cicadabirds. On Sumba, entirely black tail, lacking white, rules out Black-faced Cuckooshrike. In other areas, Wallacean is separated from Black-faced by the absence of a clean white belly, the darker upperparts, and the less distinct black face. Gives nasal, squabbling, and upslurred buzzy notes.