This is Bird Note.

A peacock's tail is magnificent, four or sometimes even five feet in length. When opened,

it's an iridescent wonder, shimmering and covered in giant spots. And as it turns out, when it comes to that wonderful tail, there is even more than meets the eye.

As this male Indian pea fowl quivers his outstretched tail, it creates a rustling sound, almost like a drum roll.

Scientists call this sound, almost like a drum roll.

Scientists call this the peacock's train rattle.

You might also call it the sound of peacock love.

That train rattle is also causing a vibration in the air that we humans can't feel. But female peacocks or peahens can.

That low-frequency rumble hits the sweet spot, also known as the resonant frequency of both the males and females' crest feathers. They start to vibrate in unison. Pfowl also do a special wing shake,

which seems to hit that same sweet spot. Scientists aren't quite sure how the train-rattle love buzz

fits into peacock mating behavior, but for the first time, we're starting to listen in.

For Bird Note, I'm Mary McCann.