Black Drongo

The black drongo is an all-black bird with a distinctive forked tail, measuring 28cm long. It is aggressive and fearless and will attack much larger birds that enter its nesting territory, including crows and birds of prey. Eggs are laid close to the first rains in April, incubated by both parents, and hatch after 14 to 15 days (Wikipedia, general species account).

The only source read for the Bhutan guide gives these details. No range, habitat or diet information was found, so none is stated, and its occurrence in Bhutan is flagged for checking.