Tiny Australian bird cries wolf to scare predators

One of Australia's smallest birds has found a cunning way to protect its nest from predators by crying wolf, or rather hawk, and mimicking the warning calls of other birds.

Researchers from the Australian National University (ANU) found that the tiny brown thornbill mimics the hawk warning call of a variety of birds to scare off predators threatening its nest, such as the larger pied currawong.

"It is not superbly accurate mimicry but it is enough to fool the predator," said Branislav Igic in a university statement.

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.

"I am amazed that such a tiny bird can mimic so many species, some much bigger than itself. It's very cunning," Igic added.

Although vocal mimicry is widespread amongst birds, its function is rarely understood.

This study is the first to show that birds use vocal mimicry to scare predators.

The researchers stumbled across the thornbill's deceit during an experiment on birds' reaction to a stuffed owl.

"I was puzzled because I could hear the alarm calls of robins, honeyeaters and rosellas but I couldn't see any," added professor Robert Magrath, the leader of the research group.

He soon realised that the brown thornbill was mimicking the other species while defending the nest.

Many species of both birds and mammals eavesdrop on the alarm calls of other species. Natural communities form an information web about danger, the authors noted.