The Black Coucal (Centropus grillii) is a species of cuckoo in the Cuculidae family. It has a wide distribution in Africa south of the Sahara. The male black coucal is 30 cm in length while the female is 34 cm, otherwise they are similar in appearance. In breeding plumage the head, body and tail are black, apart from some buff barring on the rump, and the wings are rufous. Outside the breeding season, the upper parts are dark brown with rufous barring. The eyes are brown and the beak and legs are black. Juveniles are rufous with various dark and light barring and streaking.
It is resident in some locations and migrant in others. Its habitat is marshes, savannah, grassland, bracken, undergrowth, and clearings in woodland, and occasionally reeds and papyrus. It usually occurs below 1,500 m but occasionally up to 2,000 m. In kenya it is local resident from Lake Victoria basin and Mara GR east to the Tana River delta. Seasonal in most areas ; few breeding records.
The species has the role of sexes reversed with the males tending the nest while females are polyandrous and maintain territories. Studies on the hormonal system show that progesterone is responsible for controlling the aggressiveness of females.
Source : Wikipedia