Body length is 23 to 28 cm (9.1 to 11.0 in) and wingspan range from 31 to 41 cm (12 to 16 in). Males are heavier than females. Average weight of this species is 77 g (2.7 oz).
They inhabit small islands of the Western Australia coasts, particularly Bald Island, and Rottnest Island, and the south western parts of the mainland.