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For the Adélie penguins on Petrel Island in East Antarctica, this is a critical moment. It is early summer and adult birds are returning in their tens of thousands to breed.
If all goes well, the island should soon be abuzz with the squawks of raucous chicks calling for food. Taking turns to waddle and slide across the ice, their parents fetch fish and krill to feed their hungry young. In the normal course of events, it is much as you would expect from watching Happy Feet.
But a far from happy scene greeted French scientists visiting to count the new arrivals last season. The bodies of thousands of tiny, starved chicks were strewn across the ground, their downy plumage sodden. Also dotted across the stark, glacial landscape were numerous unhatched eggs. From a breeding colony of 18,000 pairs of Adélie penguins –