The Ice Retreats

S1, E2: Spring begins in the sub-Antarctic islands with Elephant seals returning from the sea to fight for supremacy over their harems, while five million Macaroni penguins battle through the crashing waves to court and breed. Further south, spectacular time-lapse sequences reveal a continent only just being freed from the ice trap. There is also rare underwater footage of the hardier penguins as they venture south to reach their traditional breeding grounds.