A flock is one of the most spectacular sights in nature – but how does it work? The explanation comes down to some surprisingly simple rules that each bird applies to its seven closest neighbors.
The sky is one of the world's most challenging places to live, but across the planet, an extraordinary range of animals do something we can only dream of take to the air. Some spend their whole lives airborne, while others only visit. But, they all have one thing in common: they survive by taking to the skies.
LIVE