A FIVE-YEAR project to save one of Scotland's most threatened puffin colonies is already seeing swathes of the birds return to traditional breeding grounds.
Numbers of the seabirds on Craigleith island in the Firth of Forth had plummeted from 28,000 pairs in 1999 to just a few thousand last year due to the invasion of a non-native plant.
Now, thanks to hundreds of volunteers who helped remove tree mallow that had grown over the entrances to the puffins' burrows, the birds are once again raising families on the island.
Dr Rene van der Wal, of the Centre for Environmental Sustainability at Aberdeen University, said the speed of the birds' return was remarkable.
Volunteers reduced tree mallow cover to 28 per cent, and as a result 96 per cent of the burrows were now being occupied by puffins, compared to 30 per cent in areas where tree mallow was not cut back.
Dr van der Wal said: "In experimental trials on removing tree mallow, it took years for puffins to come back, so to find areas taken back by puffins straight away is quite a surprise.
"It suggests that they have just been waiting for something to happen."
He added: "Puffins have had a tough year because heavy rain has flooded many of their burrows. Removing the tree mallow will help make their lives easier."
SOS Puffin is being run by the Seabird Centre at North Berwick, Scottish Natural Heritage, RSPB Scotland, Dunbar Harbour Trust and the University of Aberdeen, and was helped by 250,000 landfill tax funding. More than 100 volunteers from across Scotland cleared three acres of tree mallow since the end of last year, just in time for the puffins returning to nest in April. They are drawn instinctively to where they are born.
Tom Brock, chief executive of the Scottish Seabird Centre, said that, despite Scotland being home to 45 per cent of all the seabirds in Europe, their survival was under threat.
He said: "In many parts of Scotland, some seabird species have had a disastrous breeding season, due to lack of food. Chicks have been starving to death.
"The initial results from SOS Puffin bring some excellent news and provide a good example of human intervention being used to positive effect. No-one expected such good results so quickly."
Tree mallow is a Mediterranean-Atlantic herb that can grow up to 3m tall and forms dense stands. Puffins abandon areas where it has invaded because they cannot get into their burrows.
It is thought the plant spread to the island from gardens. Work to remove it will need to be ongoing to prevent it growing back to threatening levels.
Live images from puffin burrows and the clifftops can be seen at the Seabird Centre and on its website. The puffins are expected to remain on the island for another week or two.