Birds
Fork-tailed Drongo
Dicrurus adsimilis · also called common drongo
The fork-tailed drongo spends its day near a group of meerkats or babblers, and it is genuinely helpful, watching for hawks and calling out real warnings. It is also, whenever it can get away with it, robbing them, using fake alarm calls to make them drop their food and run.
Overview
Dicrurus adsimilis is a glossy blue-black African songbird with red eyes and a deeply forked tail, common across the savannas and open woodland of sub-Saharan Africa. It hunts insects in fast dashes from a perch, and it is a fearless mobber of hawks and snakes near its nest.
The con
It follows foraging meerkats and pied babblers, gives true alarm calls to build trust, and then, when one of them unearths a fat grub, gives a false alarm call. The animal drops the food and bolts, and the drongo grabs it. To keep the trick working, it mimics the alarm calls of its victims and other birds, cycling through as many as 45 call types.
A calculated liar
Kalahari studies found drongos get about a quarter of their food this way, hold back false alarms until there is something worth stealing, and change calls when one stops working — flexible, tactical deception.
Status
Least Concern — common and adaptable across sub-Saharan Africa.
Fork-tailed Drongo: common questions
Does the drongo really lie to other animals to steal their food?
Yes, and it is one of the best-studied examples of tactical deception in a wild animal. Fork-tailed drongos in the Kalahari attach themselves to foraging parties of meerkats and pied babblers, spending part of the time hunting insects and part giving genuine alarm calls that warn the group of real predators. Once a meerkat or a bird has dug up a large prey item, the drongo sometimes gives an alarm call when there is no predator, the target drops the food and dashes for cover, and the drongo dives in and grabs the abandoned meal. Researchers confirmed the calls were false by checking that no predator was present, and showed that drongos time the deception for when there is something worth stealing.
Why do the meerkats keep falling for it?
Because the drongo makes the lie hard to detect. First, it tells the truth most of the time, so its alarm calls are usually worth heeding, and ignoring them risks being caught by a real hawk. Second, when its own alarm call starts to lose its effect, the drongo switches to imitating the alarm calls of the meerkats themselves, or of other birds, so the warning comes in an unfamiliar, still-credible voice. A single drongo has been recorded using dozens of different alarm-call types and rotating through them. The meerkats face a genuine dilemma, either responding and sometimes losing a meal, or ignore and sometimes be killed.
What is a drongo, and where does the insult come from?
Drongos are a family of around 30 species of small to medium glossy black songbirds found across Africa, southern Asia, and Australasia, most with a forked or racket-shaped tail, and most are bold aerial insect-hunters and fierce nest defenders. In Australian and British slang, drongo means an idiot or a hopeless case, but that has nothing to do with the bird's intelligence; it came from a racehorse named Drongo in the 1920s that ran many times without ever winning. The bird itself, as its food-stealing shows, is anything but stupid.
Is the drongo a friend or an enemy of the animals it follows?
Both, and the balance shifts. For much of the time the drongo is a useful companion. It perches high, spots danger early, gives real alarms, and its presence lets meerkats and babblers spend more time with their heads down feeding. In return it catches insects the foragers flush from the grass. The theft is a parasitic overlay on top of that broadly cooperative relationship, and the groups tolerate it because, on balance, having a drongo around still leaves them better off than not, even accounting for the occasional stolen grub.