The small predators, introduced into Britain by fur farms, are now decimating the populations of gulls, terns, cormorants and other birds that inhabit the sea lochs of the Western Highlands.
In 10 years populations between Skye in the North and the Mull of Kintyre in the South have fallen by up to 50 per cent. In some lochs, birds are still clinging on and attempting to breed although all their chicks are being killed - but in many others, such as Loch Sunart and Loch Sween, they have disappeared.
These lochs have become "like ghost towns", according to Clive Craik, a biologist from the marine laboratory at Dunstaffnage near Oban, who is studying the problem.
"Mink are now a greater threat to British seabirds than oil spills," Dr Craik said.
Natives of North America, mink began to build up a wild population in Britain in the post-war years after escapes from fur farms, and from the Sixties onwards they became strongly established.
The minks flourished because they filled an empty niche in the British ecosystem for an aquatic carnivore - a flesh-eating predator which is as much at home in the water as it is on land.
Mink are strong swimmers and this has allowed them to cause particular damage to certain wildlife species. They have wiped out water voles from many English rivers, and now the Highland seabirds.
The birds in the fjord-like sea lochs of the west coast of Scotland are particularly vulnerable because they breed on the ground in large colonies on small offshore islands where, before the mink's arrival, they were safe from predators such as foxes and stoats. Mink, however, can reach the islands with ease, where they frequently kill all the birds they find.
"They've come in the last 10 years and they're wreaking terrible havoc, taking all the eggs and chicks," Dr Craik said. "They do far more damage than their diet requires. They take the eggs and chicks and hide them."
Several species have suffered catastrophic declines, which Dr Craik - who visits the lochs seven days a week during the summer months with a small boat on his car - has graphically catalogued.
Common terns in his study area, which stretches from Mallaig opposite Skye to Campbeltown in Kintyre, have gone down from 1,839 pairs in 1987 - which was more than 10 per cent of the British population - to 1,029 pairs last year, a decline of 44 per cent.
Common gulls, which despite their name are far from common, have gone from 1,248 pairs in 1989 to 714 pairs last year, a 43 per cent decline, and black-headed gulls have gone down from 630 pairs in 1989 to 290 pairs last year, a decline of 54 per cent.
Other birds have also suffered severely although Dr Craik has not been able to record their declines in the same detail. They include cormorants, shags and herring gulls, and one of the coast's most attractive birds - the black guillemot - which also nests on the ground on the islands, and is now vanishing from the coast.
"I view it as an ornithological disaster," Dr Craik said. "If an oil spill is a disaster for seabirds, this is worse. It's far worse than the Braer [in Shetland in 1993] or the Exxon Valdez [in Alaska in 1989].
"In those cases the birds' populations went down by 15 to 20 per cent, but then they came back up, and here they are going completely.
"I find it very sad, these beautiful birds disappearing from these beautiful sea lochs. In some there's nothing now. It's like going into a ghost town. People haven't really woken up to what is happening, but I lie awake thinking about it."
Lochs where birds have stopped breeding completely include Sunart, Teacuis, Crinan, Sween, Caolisport, Tayvallich Harbour, The Sound of Luing and parts of Loch Linnhe.
Lochs where birds are still trying to breed without any success - the stage before abandonment - include Lochs Nan Ceall, Nan Uamh and Moidart.
However, Dr Craik has tried to defend the seabirds, and he has organised mink trapping forays with success in other lochs, including Ailort, Leven, Etie, Feochan, Craignish and West Loch Tarbert, where the seabirds are still breeding.
n About 1,500 of the 6,000 mink released from a fur farm at Ringwood in Hampshire by animal welfare activists a fortnight ago are still at large, police said yesterday.Reuse content