Crowded Skies

With the help of some surprising creatures from around the world, this series sets out to discover how animals take to the air, defying the force all airborne animals must conquer, gravity.

This episode features a creature that creates sound out of thin air with the world's fastest courtship display and arguably the world's most aggressive bird.

In a South American jungle, there's 'hunt and evasion' flying during the night, as bats and moths fight for the upper hand in one of the world's oldest arms races.

Plus a camera films a giant flock to unlock the secrets that keep half a million birds from colliding in the same air space.