A large dark green hummingbird of montane woodlands that often appears black. Within its range, only the Antillean Mango and Green-throated Carib are similar in size and shape. Green-throated Carib and male Antillean Mangos have black, not green, bellies. Female and immature Antillean Mangos have largely gray underparts unlike the Green Mango’s green underparts. Calls include a thin, high twitter, a sharp high "tsip".