It was Charles Darwin who initially proposed that birds not only use their wings for flight but communication as well.

Today, almost 150 years after Darwin’s suggestions, researchers have confirmed the theory to be correct, and in the process, they elucidated why pigeons make a racket when taking off.

Birds produce warning sounds

Studies into crested pigeons revealed that birds use their primary flight feathers to deliver a shrill cautioning whistles to tip off their colleagues as they take off from a danger zone.

“Birds possess such noticeable voices, we have generally disregarded their shockingly complex instrumental sounds,” leader of the study Robert Magrath said.

In the past, it was obscure whether this was primarily because of flight, but the sound has now been traced to a particular feather – the 8th primary flight feather – which is used when a threat is detected.

Till this moment, most research into avian communication has concentrated on vocal sounds, but the new result reveals pigeons “utilize their feathers as melodic instruments,” according to scientists at The Australian National University.

As a way to confirm the high-pitched sounds from the feathers were actually warning signals, in the new research, scientists shot a fast video, which they used to conduct feather-remove tests.

The experiments showed that the birds’ small eighth primary flight feather is responsible for the production of high notes with every downstroke, while the ninth primary feather produces the low notes.

The study also showed that the sound changes as the birds increase the speed of their flight, to such an extent that those escaping threats produce higher tempo sounds.

At the point when the scientists played recorded flight sounds to other pigeons, they were more prone to escape after hearing the flight of a bird with an 8th primary feather, but when they played the sound of a pigeon without the 8th feather, they just took a glance instead of fleeing.