Réunion harrier

It is about 42–55 cm long; the female is around 3–15% larger than the male. The male has a blackish head and back with white streaks. The underparts, underwings and rump are white and the tail is grey. The wings are grey and black with a white leading edge. Females and immatures are dark brown with a white rump and barred tail.

The birds are mostly silent except during the breeding season when they give a chattering threat call, a wailing courtship call and chuckling food-associated calls.

The Madagascar Harrier is larger and paler with longer wings and legs.