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This is Scientific American 60-second science. I'm Annie Sneed.

Feathers are not just for flight. They keep birds warm, become part of their nests, and help them attract mates.

And for one Australian bird, feathers even help produce an important sound, an alarm.

People had long noticed that these birds produced these loud whistles.

Trevor Murray, a postdoctoral researcher at the Australian National University.

My supervisor Rob McGraw, in collaboration with Mahingi, thought that they were used as an alarm.

So they did some playbacks and they could show quite

strongly that if you play back these sounds to other birds, they flee straight away.

So what I was really interested in was following up on that research and finding out how they

produced the sound, whether it is actually a signal, and whether it's a reliable signal.

The team focused their experiment on specific feathers and the crested pigeon's wing.

We were able to target the eighth primary feather, which is unusually narrow.

It's about half the width of the surrounding feathers.

And then we also removed, on different sets of birds, we also removed those

neighbouring feathers, the ninth primary feather and the seventh primary feather. We're able to

see that the eighth primary feather, when it was missing, the high note had completely disappeared.

So the eighth primary feather produced that high note, and the ninth primary feather, it turns out, actually produced the low note.

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