In summer, the gannet’s main food source of sardines live far out to sea. This means the birds must dive for their food, but even one small miscalculation could prove fatal. Subscribe to BBC Earth: http://bit.ly/BBCEarthSubBBC Earth YouTube Channel: http://www.youtube.com/BBCEarth BBC Earth Facebook http://www.facebook.com/bbcearth (ex-UK only) BBC Earth Twitter http://www.twitter.com/bbcearth Visit http://www.bbc.com/earth/world for all the…