This is a very good photo! The male Great Curassow and the male Yellow-knobbed Curassow are almost identical (but the females are very different). I think that the male Yellow-knobbed Curassow has a white band on the end of the tail, while the talk of the male Great Curassow is entirely black. Unfortunately, we can't see the tail in this photo. Do you have any others? The males of both species have yellow knobs, but the knob of the Great Curassow is supposed to be large, round and projecting straight upward, while the know of the Yellow-knobbed Curassow is smaller, more oval, and projects forward. My guess is this is a male Great Curassow (Crax rubra).
