Black drongos breed mainly in February and March in southern India, and until August in other parts of the country. Males and females sing in the mornings during the breeding season. Courtship can include aerobatic chases and they may lock their wings and beaks together, with the pair sometimes falling to the ground. Displays may be made on the ground. Pair bonds are retained for a whole breeding season. The nest is a cup made with a thin layer of sticks placed in the fork of branch, and is built in a week by both the male and female. Eggs are laid close to the first rains in April. The usual clutch is three or rarely four eggs laid in a cup nest placed in the fork of an outer branch of tree. Large leafy trees such as the jackfruit are preferred. The eggs are pale cream to red with spots and markings and are 26 mm (1.0 in) long and 19 mm (0.75 in) wide. The eggs are incubated by both parents and hatch after 14 to 15 days. Nestlings are brooded for the first five days, after which the young are capable of maintaining a fairly constant body temperature. A second clutch may be laid if the first is destroyed. Nests are sometimes built in telephone poles. A nesting territory of 0.003 to 0.012 km2 (0.3 to 1.2 hectares) is maintained.
Helpers, offspring from the previous brood, have sometimes been noted to assist in feeding the fledglings at the nest of their parents. Cases of brood parasitism by the Asian koel have been noted. An average breeding success of 44% has been noted with the main cause of fledgling mortality being shortage of insect food which in turn was dependent on rainfall.
Their habit of driving away predators from near their nests is believed to encourage other birds such as orioles, doves, pigeons, babblers, and especially bulbuls, to nest in the vicinity. In one study 18 of 40 nests had red-vented bulbuls nesting within 10 metres (33 ft). An abnormal case of interspecific feeding with a red-vented bulbul feeding the chicks of a black drongo at their nest has been recorded.
It has been suggested that the Asian drongo-cuckoo (Surniculus lugubris) has evolved to mimic this species. The intensity of mobbing predators was studied in Java and observations showed that there was a significant increase in mobbing, during the nesting season, of some predators such as the Javan hawk-eagle but the black eagle, a nest predator is mobbed with equal intensity in all seasons. It has been suggested that this strategy may avoid giving away the location of nests during the breeding season.
Many ectoparasitic bird lice (Myrsidea spp. and Menacanthus spp.), endoparasitic cestodes and nematodes have been described from this species. However no predators or diseases are significant factors in adult mortality.
Their habit of preying on bees makes them a nuisance to bee-keepers, but farmers attract them to their fields using artificial perches in fields to encourage them to feed on pest insects.
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