Description wikipedia

The fork-tailed drongo-cuckoo (Surniculus dicruroides) is a species of cuckoo that resembles the Black drongo (Dicrurus macrocercus). It is found mainly in hill forests in peninsular India and Sri Lanka although some specimens are known from the Himalayan foothills. It can be identified by its metallic black plumage, straight beak, white barred vent, forked tail and white spot on the back of the head. The fork-tailed drongo-cuckoo's song has been described as a series of 5 or 6 whistling "pip-pip-pip-pip-pip-" notes rising in pitch with each "pip". They are also known for their drongo-like calls such as "quip" calls in flight and "wheep-wheep" call with a higher second note. In Sri Lanka, the fork-tailed drongo-cuckoo also has similar calls to the Sri Lanka Drongo (Dicrurus lophorinus). It is a brood parasite on small babblers. It is not known how or whether the drongo-like appearance benefits this species but it is suspected that it aids in brood-parasitism just as hawk-cuckoos appear like hawks.