This 2011 video, recorded in Scotland, says about itself:
Atlantic puffins return to the Isle of May each summer where they breed in their tens of thousands. Challenges abound, including the threat of predators, squabbles over burrows and finding a mate. Towards the end of the season, newly hatched pufflings face the journey to their ocean home alone under cover of darkness.
Mysteriously, during recent years the puffins have been facing an even greater challenge that has caused a dramatic population decline. Up to 30% of breeding puffins have simple disappeared. What is the force behind this alarming decline?