Scotland's rat pack flies into action

But for 250 years the islands have been overrun by rats and mice which came ashore from whaling ships in the late 18th century, threatening the vulnerable wildlife.

Now, in an ambitious bid to turn back nature's clock, a Scottish-led team of experts will travel 7,880 miles to launch the world's largest ever rat eradication programme on the windswept and rocky island.

The aim of the scheme is to completely wipe out the "countless millions" of rats and mice living on South Georgia by using a specially formulated poison which will kill the rodents but pose only a negligible threat to the native seabird populations.

The islands are the breeding ground for 31 bird species ranging from the black browed albatross, a seabird with one of the largest wingspans in the world, to the tiny Wilson's storm petrel.

The 7 million four-year project is headed by the Georgia Heritage Trust, which is based in Dundee, and is being led in South Georgia by Professor Tony Martin, head of animal conservation at Dundee University.

Prof Martin said: "The challenge is daunting, but the South Georgia Heritage Trust stands ready to meet it.

• Bird's island refuge

"Our objective is simple - to remove every single rodent from South Georgia and its outlying islands by the year 2015, and working with the government of South Georgia, ensure no rodents ever return.

"We have a unique opportunity to roll back two centuries of human-induced damage to this island and its wildlife. The scale of the challenge is daunting, but the conservation rewards cannot be over-stated - literally millions of seabirds will reclaim South Georgia from the rats.

"I am excited and privileged to play my part in this globally important operation."

Alison Neil, the trust's chief executive, said it was one of the most ambitious conservation projects in the South Atlantic.

"South Georgia is one of the musty important seabird sanctuaries in the world. But the rats are devastating the ecology of the islands," she said.

"They eat the chicks and eggs of literally millions of birds every year. No-one really knows just how many rats there are but it is probably in the millions."

Ms Neil said that before the rats arrived, the birds had no natural predators apart from other birds."And all of the birds nest on the tussock grass and have nowhere to nest safely away from the rodents," she added.

Today, in the first phase of the programme, two helicopters will begin spreading 58 tonnes of bait.

"The bait, in the form of a cereal pellet, has been specially designed for the island conditions and to put off the birds from eating it," Ms Neil said.

"It is a bluish colour, which we know birds don't like. And we expect the majority of the rats will die underground because the bait makes them sensitive to light.

"We do, however, expect some primary and secondary poisonings. It would unrealistic to think otherwise. Scavengers such as gulls may well eat the bait.

"We will wait until 2013 to start the second part of the operation to confirm that our methodology has been right and that all the rats have indeed gone."

Ms Neil said in world conservation terms, there were many endangered species threatened by the rats.

"We are going to increase their numbers by many millions by removing the rodents from the islands," she said.

"We believe the technology is there to eradicate all the rats that live on South Georgia. But the main concern we have is to raise the cash we need to complete the project. We have raised 1.6 million and need another 5m."