The exact impact of the non-native rodents on the Shiant islands in the Minch, Outer Hebrides - home to more than 150,000 seabirds that breed there each year - is unclear.
But the rats, which came ashore about 1900 from shipwrecks, are known to devour seabird eggs and young chicks. Removing rats from islands has demonstrable benefits for breeding seabird populations.
Plans to tackle the menace have been given a boost after £450,000 of European Union funding was awarded yesterday to the Shiant Seabird Recovery Project.
It aims to create favourable conditions to attract the birds to the islands to breed alongside the resident puffins and razorbills.
The overall cost of the project is about £900,000.
The islands are one of the most important seabird breeding sites in Europe. They support 10 per cent of the UK's puffin population and seven per cent of the UK's razorbills, and have been designated a Special Protection Area for Wild Birds.
Two other species, the Manx shearwater and European storm petrel, are now restricted to a small number of island locations on the west coast.
They continue to be threatened by factors such as climate change, pollution and a shortage of breeding sites.
Neither species is resident on the Shiants, but there is an abundance of suitable habitat, and some evidence that shearwaters once bred there.
The project will use recordings of calls to attract the birds and will carry out active management to make sure the birds have the best opportunity to settle and breed. A significant challenge will be removing the black rat. The exact impact of these non-natives on the Shiants is not fully known. However, studies have shown they will eat seabird eggs and young chicks.
The project to remove the rats is a partnership between RSPB Scotland, Scottish Natural Heritage and the Nicolson family, who have been the custodians of the Shiants for three generations.
The experience will be used to prepare a plan to protect other islands from non-native predators.
Adam Nicolson said: "This is a great opportunity to return the Shiants to what they should be: even more full of life, with more bird species and more resilient in the face of future threats.
"We hope that as a result of this very exciting project, generations of people will come to know the islands as they should principally be known - that is as one of the greatest of all hubs of Atlantic seabird life."
George Campbell, RSPB regional director for North Scotland, said: "Scotland's globally important seabirds are suffering chronic declines and we have a responsibility to do everything we can to reverse these trends.
"Eliminating the invasive rats on the Shiant Isles will ensure safe breeding sites for struggling seabirds and allow the recovery and restoration of the island's existing colonies, as well as encourage Manx shearwaters and storm petrels to breed there.
"We are hugely grateful to the European Commission, Scottish Natural Heritage (SNH) and our supporters who will allow us to make these islands a seabird haven once more and contribute to shoring up our threatened seabird populations."
Andy Douse, SNH's Shiant Seabird Recovery Project ornithologist, said: "This is an exciting project that will address the problems facing one of Scotland's finest concentrations of breeding seabirds. It will also provide us with a better understanding of rat control methods that can be used more widely and it will promote better biosecurity for islands that remain or have been cleared of invasive rats."