Black Drongo

BirdAsia

Nov 5

Dicrurus macrocercus

The black drongo keeps its neighbourhood clear of predators by fearlessly assailing them — as a result, other birds like orioles, doves, babblers, and bulbuls like to nest near the drongo. But the drongo is also a trickster, mimicking the calls of raptors to scare birds into abandoning their food.

The Charcoal Bird

A fire rages across the grassy scrub. The flames crackle and lick at the dry vegetation, consuming and growing, billowing dark smoke. Amidst the blazing grass and in the ashen air, hundreds of tiny creatures flee the flames. Ants and beetles scurry, grasshoppers leap, and moths, bees, and dragonflies take to the air to escape the scorching heat. And around this inferno dances a dark shadow, like a living coal expelled from the flames. It flits acrobatically through the air — arching, diving, and swerving — keeping to the edges of the spreading fire. In its beak, it captures the insect swarms, exposed while fleeing for their lives. It revels in this infernal feast.

Perhaps it's fitting that a charcoal-black bird is fond of fires. The plumage of the black drongo is a deep and uniform inky black, although, in the right light, it shimmers iridescent blue and green, like an oil slick. Its feet and bill are an ashen grey and its eyes are a dark chestnut. Its tail feathers hang like a pendulum, the ends forked in two — a conspicuous characteristic of drongos.

From northern Pakistan in the west, through India to Sri Lanka, eastwards to Korea, and south through Indonesia, the black drongo's domain is vast. Like a severed shadow, it flutters over wetlands and meadows, forest edges, fields, and farmland. In dry savannah and scrublands, where grasses are prone to fires, the black drongo hastens to the signal of smoke, where it knows that its favourite prey — usually hard-to-find insects and small reptiles — will be forced into the open, where the drongo can exploit their misfortune.

Acrobat, Trickster, Serial-Killer

The black drongo wakes at very early dawn, before any other bird has stirred. It clings to a tree branch with its small, sharp-clawed feet, its posture ramrod straight. Suddenly, it releases its grip and falls into a swooping dive, before abruptly reversing and shooting back upwards, sweeping close alongside branches and twigs to disturb any hiding insects. Once frightened into the air, the quarry is swiftly captured, and the drongo promptly returns to its perch to devour its catch.

But, if the black drongo can get someone else to flush out its prey — or better yet, catch it — it will happily take full advantage. Just as fires expose masses of fleeing critters, a ploughed field is a veritable banquet of upturned caterpillar and beetle grubs. Although drongos typically hunt alone, such occasions call for large congregations of up to 35 individuals. With few trees around in farmlands, these shadow birds use what's available — sometimes farmers will provide perches specifically for drongos, encouraging them to pluck the pests from their crops. But, if no such perch is made available, the drongos might just choose to alight on the farmer's cattle (there exists a superstition in Central India which says that a cow, if sat on by a drongo, will lose its horns).

Although the black drongo probably doesn't cause cattle to drop their horns, it is somewhat of a trickster. It is a skilled songster and mimic, with an extensive vocal range. The drongo likes to hang around cattle egrets and common mynas — birds with similar dietary preferences. On rare occasions, the black drongo has been observed mimicking the calls of a shikra (a small but deadly raptor) to frighten common mynas from their prey. The drongo then swoops in and steals the myna's abandoned meal.

Certain black drongo populations, such as those in Korea, are migratory, although their movements are poorly understood. Migration often puts extra demands on energy and the drongos are thought to compensate by expanding their diets. A mostly insectivorous diet is supplemented with flowers, nectar, grains, fish, small reptiles, bats, and even small birds. In Korea, an event was recorded that reads like a report on a serial killer; a migrating black drongo was seen catching one bird after another, killing each with a strike to the back of the head and then feeding on the choicest parts, most eagerly on their brains. Certainly, this behaviour may not be typical of drongos — this was just one, potentially psychotic, individual.

The Neighbourhood Guard

After what you've just read, you'd think other birds would try to distance themselves from the black drongo, but the exact opposite is true. The black drongo is extremely territorial, but selectively so. It's at its most defensive during breeding season (anytime from February to August), however, it stays on guard all year round. Any potential predator, especially larger birds like crows and raptors, is fearlessly assailed by black drongos, who often act together to mob their target.

As a result, the "neighbourhoods" around black drongo nests tend to be some of the safest real estate, and non-predatory birds — including orioles, doves, pigeons, babblers, and bulbuls — will choose to build their nests close to that of a guardian drongo. A red-vented bulbul has even been seen feeding a black drongo at its nest; an exceptional occurrence, and, if we're being romantic, perhaps a form of repayment or gratitude.

The Cuckoo-Drongos

A common cuckoo (*Cuculus canorus*) on the left and a Eurasian sparrowhawk (*Accipiter nisus*) on the right.

Cuckoos are notorious for their habit of brood parasitism¹ — that is, laying their eggs in the nests of other bird species, forcing them to become unwitting foster parents to grotesquely oversized chicks. Many cuckoos succeed through deception. They evolve eggs sized and patterned in the same way as their host's eggs. Cuckoo chicks mimic the sound of an entire nest of hungry chicks, making their foster parents feed them around the clock. But to get its egg into a host nest, a cuckoo must first get close enough — and some nesting birds, as we've seen with the black drongo, can make this very difficult.

Certain species, like the common cuckoo, imitate the sounds of a raptor to distract and frighten its songbird hosts. The female cuckoo then sneaks in her egg while the hosts are too ruffled to be overly perceptive. Not only does the common cuckoo sound like a raptor, but it looks like one too — specifically a sparrowhawk. But again, this is to frighten the warblers and tits that it parasitises, and the common cuckoo doesn't target actual sparrowhawk nests. But, are there any brood parasites that use disguise to infiltrate a host nest?

A square-tailed drongo-cuckoo (Surniculus lugubris) on the left and a fork-tailed drongo-cuckoo (*Surniculus dicruroides*) on the right.

There exist four species of cuckoos which look a great deal like drongos — appropriately named drongo-cuckoos. Two species, the square-tailed and fork-tailed drongo-cuckoos, overlap in range with the black drongo. They too are clad in all black with hanging pendulous tails, but are smaller in size, with downcurving bills and bars of white beneath their tails. At a distance, however, they make for very convincing, genuine-looking drongos. How would they benefit from looking like the black drongo? Does it allow them to discreetly sneak into drongo nests?

It doesn't seem so — the drongo-cuckoos don't target the drongos as hosts. Instead, their victims are babblers, bulbuls, and shrikes. It's likely that the cuckoo-drongos play drongo-dress-up for the same reason that common cuckoos look like sparrowhawks; to intimidate their hosts. But the drongo seems an odd bird for a cuckoo to mimic, since the drongo doesn't regularly target songbirds as prey. Perhaps the black drongo's bold reputation is enough to fluster other birds. Or, perhaps — and this is just a hypothesis — the babblers and bulbuls don't shoo the cuckoo-drongos because they see drongos as useful allies that keeps away predators like raptors and crows. And so the cuckoo-drongos ride on the back of the real drongo's good reputation.

"King Crow"

The black drongo's bold nature and black plumage has given it the nickname of "king crow". It isn't a crow, of course, but it is distantly related to the corvids.

The drongos constitute some 30 species in the family Dicruridae. Although unique among the passerines (the order of perching birds), the drongos are placed with several other families into the superorder of Corvoidea. This does include the corvids (crows, ravens, magpies, etc.), but they're a more distant relative to the drongo. On the family tree, the closest group to the drongos are the fantails (family Rhipiduridae) and monarch flycatchers (family Monarchidae).

You'll find drongos from the southern tip of Africa to the borders of the Sahara (fork-tailed drongo), on Madagascar (crested drongo), throughout the Indian subcontinent (black drongo), mainland Southeast Asia (greater racket-tailed drongo), the Philippines (short-tailed drongo), Indonesia (Wallacean drongo), and Australia (spangled drongo).

From left to right; a fork-tailed drongo (*Dicrurus adsimilis*), crested drongo (*Dicrurus forficatus*), greater racket-tailed drongo (*Dicrurus paradiseus*), short-tailed drongo (*Dicrurus striatus*), and a spangled drongo (*Dicrurus bracteatus*).

Clockwise from left; brown-headed cowbirds (*Molothrus ater*), a village indigobird (*Vidua chalybeata*), and black-headed ducks (*Heteronetta atricapilla*).

¹ Cuckoos, comprising the order Cuculiformes, get a worse rap than they deserve. Out of the 150 or so cuckoo species, only around 40% are brood parasites, while the rest care for their own young. And cuckoos aren't the only birds known to shunt off their parenting responsibilities.

The cowbirds (genus Molothrus) are obligate brood parasites, meaning that they have to lay their eggs in other birds' nests. But they don't just lay them and leave. The brown-headed cowbird watches its hosts closely, and if it sees the hosts eject or neglect its egg, the cowbird retaliates by destroying all of the host's eggs — what's known as “mafia behaviour”. Other brood parasite birds include the indigobirds (family Viduidae), the honeyguides (family Indicatoridae), and even a duck (the black-headed duck).

**Where Does It Live?**

⛰️ Savanna, shrublands, fields, and urban habitats.
📍 South and Southeast Asia; from southwestern Iran, through India, China, and down to Indonesia.

‘Least Concern’ as of 12 June, 2024.

IUCN

Size // Small
Wingspan // N/A
Length // 28 cm (11 in) in total length
Weight // 50 grams (1.7 oz)
Activity: Diurnal ☀️
Lifestyle: Solitary/ Pair (during breeding season) 👤/ 👥
Lifespan: N/A
Diet: Insectivore
Favorite Food: Any kind of insect 🐜
Class: Aves
Order: Passeriformes
Family: Dicruridae
Genus: Dicrurus
Species: D. macrocercus

The black drongo usually wakes in the early dawn, before any other bird.

When hunting, the drongo sits on a perch, periodically letting go into a diving swoop before shooting back up again, sweeping alongside branches and twigs to flush out any hiding insects. With prey in its beak, the drongo returns to its perch to eat.

Typically lone hunters, black drongos will flock to ploughed fields in congregations of up to 35 birds. The churned dirt exposes a banquet of upturned caterpillar and beetle grubs and farmers will even erect perches to encourage drongos to come and eat crop pests.

Sometimes drongos will use livestock, such as cows, as perches — there also exists a superstition in Central India which says that a cow, if sat on by a drongo, will lose its horns.

These charcoal birds are often attracted to wildfires — feasting on the buffet of insects fleeing for their lives.

On rare occasions, the black drongo has been observed mimicking the calls of a shikra — a small but deadly raptor — to frighten common mynas from their prey, which the drongo promptly steals.

Black drongos can be found in South and Southeast Asia; from southwestern Iran, through India to Sri Lanka, China, and down to Indonesia.

Certain black drongo populations, such as those in Korea, are migratory, but their seasonal movements have been little studied.

One migratory drongo in Korea was observed catching one bird after another, killing each with a strike to the back of the head and then feeding on the choicest parts, most eagerly on their brains — however, this behaviour isn't known to be widespread among the species.

Black drongos are incredibly territorial, fearlessly mobbing threats like crows and raptors, especially during their breeding season (anytime from February to August).

Because of their defensive natures, the areas around drongo nests are usually quite safe for other birds too, and many — including orioles, doves, pigeons, babblers, and bulbuls — will build their nests near drongos.

The black drongo belongs to a family (Dicruridae) comprised of some 30 species. The closest relatives to the drongos are the fantails (family Rhipiduridae) and monarch flycatchers (family Monarchidae).