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Gangster Birds

December 13, 2010

In the Kalahari desert, a gangster-like bird provides protection to other birds, but at a high price.

Transcript

BOB HIRSHON (host):
An avian protection racket…I’m Bob Hirshon and this is Science Update.

Parasitic birds called drongos are notorious for giving off false alarm calls, which scare their victims into dropping their food and running for cover. But a new study suggests that the relationship might not always be one-sided. In the Kalahari desert, pied babbler birds forage while drongos perch above them. In addition to raising false alarms, the drongos call out when real predators approach, according to University of Bristol behavioral ecologist Andy Radford.

ANDY RADFORD (University of Bristol):
So they’re not all bad.

HIRSHON:
Not worrying about predators allows the babblers to focus on foraging.

RADFORD:
When they know the drongo is watching out for danger, they spread out more widely. They spend more time digging in the sand, so they actually catch more food when the drongos are around than when there are no drongos there at all.

HIRSHON:
This, in turn, gives the drongos more opportunities to steal food. I’m Bob Hirshon, for AAAS, the science society.