A large coucal of lowland forest. Note all black plumage and pale bill with red eye. Found in thick cover of humid forest where it is very skulking and difficult to see. Similar to Lesser Black Coucal, but Greater Black Coucal is more often found in forest, and is larger with a red eye and paler bill. Heard far more often than seen. Call, a short phrase of deep hooting notes. A rising and falling ”Boop-bip-boo-boo”.