Birds
Drongo
Dicruridae · also called drongos
A drongo has figured out a genuinely devious trick: sounding a convincing false alarm, sometimes borrowing another species’ own warning call, at exactly the moment a nearby animal has found food, then swooping in to steal it once the startled victim flees. Some drongos even vary the deception over time, apparently so their targets never quite learn to ignore it.
Overview
Drongos, family Dicruridae, are fiercely territorial insectivores found across forest, forest edge, and savanna in Africa, Asia, and parts of Australia. Many species have a long, deeply forked tail, and several are accomplished vocal mimics well beyond their food-stealing false alarms.
A bluff that keeps working
Varying which false alarm call is used, and how often, appears to help keep the deception effective against animals that might otherwise learn to ignore it. Despite their modest size, drongos also aggressively mob and drive off birds of prey and other intruders far larger than themselves near their nests.
Status
Least Concern — widespread and adaptable across Old World tropical and subtropical habitat, secure thanks to a flexible diet and considerable behavioural resourcefulness.
Drongo: common questions
How does a drongo trick other animals into dropping their food?
A drongo will sometimes give a false alarm call, including an accurate imitation of the specific alarm call normally used by another bird or mammal species nearby, timed to coincide with that animal having just captured or found a food item, startling it into fleeing or abandoning the food out of apparent fear of a predator, at which point the drongo swoops in and takes the abandoned food for itself.
Do the animals being tricked ever catch on to the drongo's deception?
Research suggests that some drongos vary which specific alarm call they use against a given target and adjust how frequently they attempt the deception, which may help prevent a target species from simply learning to ignore a single repeated false alarm over time, effectively keeping the trick believable and useful for longer than a fixed, unchanging deceptive call might remain.
Why do drongos attack birds of prey much larger than themselves?
Drongos are noted for unusually bold, aggressive territorial defence, mobbing and diving at potential threats, including considerably larger birds of prey, that venture too close to their nesting territory, a high-risk strategy that likely helps drive off genuine threats to eggs or chicks despite the significant size difference between the drongo and the intruder it is confronting.
Are drongos found in the Americas?
No, drongos are an Old World bird family found across sub-Saharan Africa, southern and eastern Asia, and parts of Australia and nearby islands, with no naturally occurring populations in the Americas, where different, unrelated bird groups occupy broadly similar aerial-insect-hunting ecological niches.