An African penguin who became a wildlife celebrity after being rescued from an oil slick has been spotted for the first time in almost four years.
The metal band attached to Peter's flipper gave him away
Peter the penguin's progress was monitored via a satellite tracking device when he was released back into the wild after the spill in June 2000.
Scientists charted his 800km (500-mile) swim back to his Robben Island nesting ground, but were unable to find him.
The mystery was solved when penguin watchers saw him lazing on the rocks.
British physicist Peter Barham, who is working on a project for environmental charity Earthwatch, identified Peter by the number on a metal band attached to his flipper.
Earthwatch spokeswoman Natalie Pritchard told BBC News Online: "Peter has been very clever at keeping undercover. They thought they would never see him again."
Peter became the world's best-known African penguin after a ship carrying 1,400 tonnes of oil sank off the Cape Town coast in June 2000.
Oil leaking from the wreck of the Treasure threatened the penguin colonies at Robben and Dassen Islands, which are home to more than 40,000 of the birds - roughly 40% of the world's African penguin population.
But they were saved by environmentalists who removed them from the islands, cleaned them up and took them to Port Elizabeth, where they were released into the sea.
Peter was one of three penguins who were fitted with small satellite transmitters to track their progress back to Robben Island, and ornithologists all over the world were able to follow the epic journey through the internet.
Peter was the first to reach home, but no-one had managed to confirm his arrival with an actual sighting until now.
Earthwatch says that thanks to conservation programmes, the South African penguin population is 19% larger than it would otherwise have been.