Their number in the Falkland Islands has tumbled 30 percent in just five years, from 298,496 pairs in 2000 to 210,418 in 2005/06, said the Royal Society for the Protection of Birds.

"The decline of the rockhopper penguin in the Falkland Islands suggests a massive shift in the ecology of the Southern Ocean, possibly linked to climate change," said RSPB biologist Dr Geoff Hilton.

The figures show an even more alarming drop over a longer period -- in 1932, there were one and a half million pairs of rockhopper penguins. There has been a decline of around 85 percent since then.

Rockhopper penguins are instantly recognisable because of their spiky, yellow plumage.

In "Happy Feet", American comedian Robin Williams provides the voice for one of the creatures.