Black drongo

29 cm

Black drongos become active very early at dawn and roost later than many other birds. They feed mainly on insects such as grasshoppers, cicadas, termites, wasps, bees, ants, moths, beetles and dragonflies. They sometimes fly close to tree branches, attempting to disturb any insects that may be present. They congregate in fields being ploughed, picking up exposed caterpillars and beetle grubs. As many as 35 birds have been seen at such congregations. They are also attracted to fires in scrub and grasslands habitats where insects are disturbed. They appear to avoid flies. They associate with common mynas, cattle egrets and other birds that share a similar diet and habitat. Drongos benefit from this association and are more successful in their foraging. There is only partial overlap in the insect prey sought by mynas and drongos although in rare instances the drongos may rob prey from mynas. It is said that they imitate the call of the shikra so as to put mynas to flight and then to steal prey. Similar behaviour, using false alarm calls, has been noted in the fork-tailed drongo. There are some cases of the black drongo preying on small birds, reptiles, or maybe even bats. It has been suggested that they may feed on birds more intensively on migration. An individual on a migratory stop-over island in Korea caught several birds one after the other, killing them by striking at the back of the head and neck and feeding selectively on parts, especially the brain. They have also been on occasion seen feeding on fish Flowers of trees such as Erythrina and Bombax may be visited for water and nectar and they are sometimes known to feed on grains. They are only rarely known to take larger arthropods such as scorpions and centipedes. They feed on milkweed butterflies that are often avoided by other predators and are known to feed late in the evening or night, often on insects attracted to artificial lights.

The black drongo is found predominantly in open country and usually perches and hunts close to the ground. They are mostly aerial predators of insects but also glean from the ground or off vegetation. They are found as summer visitors to northeastern Afghanistan and northern Pakistan but are residents from the Indus Valley until Bangladesh and into India and Sri Lanka. Some populations show seasonal movements that are poorly understood while populations in Korea are known to be migratory. The black drongo can be found in savanna, fields, and urban habitats. Black drongos were introduced just before the Second World War from Taiwan to the island of Rota to help in the control of insects. It is believed that they dispersed over the sea to the island of Guam in the 1950s. By 1967, they were the fourth most commonly seen birds in roadside counts on Guam and are today the most abundant bird there. Predation by and competition from black drongos have been suggested as factors in the decline of endemic bird species such as the Rota bridled white-eye and the Guam flycatcher.