CANBERRA, Nov. 10 (Xinhua) -- A common species of Australian pigeon uses the sound of its feathers to warn of impending danger, a local study has found.
Researchers from the Australian National University (ANU) found that rather than using vocals, the crested pigeon uses a high-pitched sound produced by its main flight feathers to warn fellow pigeons of predators.
As the pigeon flaps faster to escape danger, the tempo of the alarm signal automatically increases.
Trevor Murray, an animal communication expert from ANU, said on Friday that the team is able to prove that other crested pigeons flee when they hear the warning, proving it is used specifically as an alarm rather than a by-product of flight.
"Crested pigeons signal danger with noisy wings, not voices," Murray said in an ANU media release.
"It shows that birds really can use their feathers as 'musical instruments' to communicate with others."
In order to prove that the pigeon's whistling feather was an alarm system, researchers used high-speed video and conducted feather-removal studies.
They found that the bird's eighth primary wing feather was responsible for the high-pitched notes with each downstroke.
It was also discovered that the ninth feather produces a low-pitched sound that it was not involved in the alarm.
Researchers played flight sounds of crested pigeons with and without their eighth feather to a flock of other pigeons.
"We show that the crested pigeon produces an acoustic alarm signal with its wings and that it is an intrinsically reliable signal of danger," Murray said.
"The alarm signal is intrinsically reliable because pigeons flap faster to escape predators, and this fast flapping automatically produces the high-tempo alarm signal."
