The Paradise Whydah, also called Eastern and Long-tailed Paradise Whydah, comes from East Africa.
The male, above, grows an extremely long tail for his breeding plumage, over three times the length of his head/body. He also develops an orange chest and black head/back.
The male's long tail, orange chest and black head and back are moulted out after the breeding season and his plumage looks the same as that of the female.
The above bird is a male beginning its breeding plumage; the female has only the black streaks and not the black spots on her head.
The end of the male breeding plumage (and centre below)
Parasite Whydah would be a more appropriate name. All Whydahs are "cuckoos" or brood parasites: they lay their eggs in the nest of a host finch, although they don't destroy their hosts eggs.
In the case of the Paradise Whydah, the Green-winged Pytilia is the chosen host and the young Whydah learns its song from the foster parent.