They received an enthusiastic welcome from naturalists and tourist representatives with the Mayor of Killarney, Sheila Casey, greeting the aircraft that flew them in from Norway. But a very different "Eagles go home" message was conveyed by sheep farmers, more than 100 of whom gathered with placard to protest at the project. They fear lambs will be in danger from the birds of prey, which will grow into formidable predators, weighing more than 7kg. They will have a wingspan of more than 8ft, with broad "barn-door" wings.

The eagles have taken young lambs in Scotland, where they have also been reintroduced, although there is uncertainty and debate about the scale of the risk they pose.

Ireland's sea eagles were brought from Trondheim in a first-class compartment, accompanied by Irish experts. They will now go through several weeks of conditioning, during which they will have minimal contact with humans so they can prepare them for the wild.

They will first be released into Killarney National Park, though it is presumed they will then move to the coast. A large part of their diet consists of fish, which they can pluck from just under the surface of the water.

Apart from the occasional lamb, they also consume ducks and other birds and rabbits, which they either take live or find dead. Their huge size and power also allows them to intimidate other birds and animals into abandoning their food to them.

Local authorities and tourism interests have strongly supported importing the eagles, whose fierce glamour will, they hope, prove an additional attraction for an already popular area.

Eamonn Meskell, of the National Parks and Wildlife Service, which helped organise the project, said it was part of the commitment to maintain and enhance native Irish wildlife in line with the country's obligations under the UN convention on biological diversity.

The Irish Republic has already reintroduced golden eagles in Donegal, where last month a wild chick was hatched there for the first time in a century, amid celebrations by naturalists. More than 40 birds have been released there in recent years.

A local naturalist, Lorcan O'Toole, said: "This little chick is another positive step in the work of seeing these magnificent birds firmly re-established in Donegal and down the west coast of Ireland. Maybe it is another sign that we are rediscovering our traditional respect for our landscape." Eagles were wiped out in Ireland by farmers and gamekeepers who regarded them as a menace to livestock.

Neilie O'Leary of the Irish Farmers' Association said he had discovered on a fact-finding mission to the Isle of Mull, in the Inner Hebrides, that one farmer there had lost 28 lambs from a flock of 130 ewes. Mr O'Leary called on the Wildlife Service to join in a management strategy similar to that in place on Mull, so that eagles and lambs could be protected. He added that Scottish farmers received funding of several thousand euros a year.