They are a small bird, about long and weighing about . The young males and females look the same, with grey to green, brown and dark brown feathers. The belly is coloured a pale brown to cream color, with dark olive to grey crescent shapes. When the male becomes sexually mature at about seven years old he grows black feathers, with a shiny blue-purple shine. The male also has bright blue eyes, and a blue beak which is yellow on the end. 