The Greater Racket-tailed Drongo, Dicrurus paradiseus, is a medium-sized Asian bird. The drongos are
passerines restricted to the Old World tropics. They were previously classed as the family
Dicruridae, but that has been much enlarged to include a number of largely Australasian groups, such
as the Australasian fantails, monarchs and paradise flycatchers. These are aggressive and fearless
birds, 32 cm in length, and will attack much larger species if their nest or young are threatened.
This aggressive drongo is often found in mixed feeding flocks typical of Asian jungle habitats. They
are said to imitate raptor calls so as to alarm other birds and steal prey from them.

Source: Wikipedia