African bird steals food by imitating warning calls

The forked tailed drongo bird of Africa -- quite the trickster --imitates multiple species' warning calls to scare off other animals and steal theirfood, a study published Thursday revealed.The birds often use their own danger alert to trick their fellow bird and beast intoabandoning a meal, but researchers were puzzled why animals never wise up to thefalse-warning scheme.After following 64 drongos over the course of 847 hours, however, the scientistsfound that the bird can mock up to 51 other bird and mammal alert noises,including the mongoose and jackal.Because the drongo can imitate so many species' warnings, animals do not get usedto the bird's own false alerts, the biologists said in a study that appeared in thejournal Science.When the bird's alert cry is no longer taken seriously, the drongo switches toanother species in its repertory, said author Tom Flower, a biologist at theUniversity of Cape Town in South Africa.The unique gift allows the Drongo, a black bird with a metallic sheen, that weighsbetween 2.5 and 4.5 ounces (70 to 125 grams), to exceed the normal vocalconstraints that generally limit such imitations in nature.Animals are often capable of recognizing other species' cries of danger.Flower and his colleagues carried out their studies in the Kuruman River Reserve inthe Kalahari Desert, observing the birds during 688 attempts to seize food fromtheir animal neighbors.According to the researchers, the birds were able to steal up to a quarter of the foodabandoned by the animals they make flee.