Good girl.
No.
And now it's Kenza's turn.
-Did you hear anything? -That was pretty good.
No, nothing at all, Absolutely quiet.
It's amazing.
But what have the microphones picked up?
The decibel waveform show the sound being generated by the birds in flight.
Each spike is an individual wing beat.
But with the barn owl...
there's almost nothing.
Even our array of super sensitive microphones failed
to pick up any sound of Kenza in flight.
And here's the owl doing exactly the same.
Nothing. Nothing at all. I'll play it again.
There's not a sound here.
-That is really impressive, isn't it? -Yeah.
It shows that they really are silent fliers.
So, how does a bar now fly so silently?
When air moves, it generates sound.
The more movement, the greater the sound.
The pigeon's large body and small wings
mean it can't stay airborne without a lot of fast flapping.
This creates turbulence in the feathers below.
The Peregrine has much larger wings,
which it uses to build up speed and chase down its prey.
The barn owl is far more graceful.
Kenza's large wings and small body make it easier for her to generate lift.
So, just one gentle wing beat sees her gliding effortlessly through the air...
creating little more than a whisper in the feathers below.