Tiny bird mimicks hawk warning to fend off predator

A bird weighing just two teaspoons of sugar scares off a predator 40 times its size by imitating the "hawk alarm" of other species, scientists said Wednesday. The trick is used by the brown thornbill, one of Australia's tiniest birds, to scare off its much larger enemy, the pied currawong, they reported in Proceedings of the Royal Society B. The eight-gram (0.28-ounce) tiddler artfully copies the warning cry used by other bird species against attack by the goshawk - a predator even bigger and scarier than the currawong.
This distracts the currawong, fearing a hawk attack may be imminent, and gives the thornbill's nestlings enough time to take shelter. Mimicry is a common defence in nature, but the researchers were stunned at how effective this tactic is. They stumbled upon the trick during an experiment on birds' reaction to a stuffed owl. "It's very cunning," said Branislav Igic, who conducted the study at the Australian National University. "It's not superbly accurate mimicry, but it's enough to fool the predator. "A physical attack on a currawong would be no good. They are 40 times the size of a thornbill and will eat adults as well as nestlings."