Answer:
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
What lies in a tunnel of darkness. That can only attack when pulled back?
Voiceless it cries, wingless flutters, toothless bites, mouthless mutters.
It's anything but amusing when this body part gets hit.
What makes a loud noise when changing its jacket, becomes larger but weighs less?
All about, but cannot be seen, Can be captured, cannot be held, No throat, but can be heard. Who am I?