Drongos, African Kalahari Desert birds with a penchant for thievery, are taking a turn towards the avian equivalent of organized crime, a new study finds.
The victims in this case, pied babblers, have long contended with the risk of drongos popping in to make off with the babblers’ hard-earned insect prey. Now it seems a set of behaviors have evolved that are taking this interaction from a purely parasitic relationship to one of more mutual benefit. Researchers found that the drongos form protection squads for foraging babblers, keeping an eye out for trouble and strong-arming danger when it arrives.
“Like any good gangster,” says Andrew Radford, a scientist with the University of Bristol who led the research team, “as well as lying and stealing, the drongos also provide protection by mobbing aerial predators and giving true alarm calls on some occasions.”
That means pied babblers can spend less time watching for predators and more time looking for prey. The relationship is not without its caveats. Drongos still aim to take advantage of babblers, crying wolf to scare the babblers and grab the insects. The babblers likely put up with it, the researchers say, because the benefit of not having to worry about predators outweighs the cost of the drongos’ antics.
The research, which is a collaboration with the Universities of Bristol, Cambridge and Cape Town, is published online in the current issue of Evolution.