Something is missing from even the wildest of Irish mountains - some extra edge of awe and expectation that reaches beyond their rugged physical form. Could it be because there is no hope of eagles, no hint of the great bird that, soaring round cliff and crag, inscribed the mountain's contours on the sky?
In the middle 1800s, one could have seen a dozen eagles in a day in the mountains of Kerry, or could have watched them swooping after hares or grouse, from Connemara to Achill to Donegal. The main work of their extinction took a mere 50 years, as gamekeepers and shepherds used rifles, traps and strychnine, and collectors then vied for the final eggs and young. Ireland is the only country in the world to have lost its golden eagles in such recent times.
The last two pairs of native birds nested on the heights above Glenveagh, Co Donegal, in 1910, and on the remote cliffs of north Mayo in 1912. An eagle shot in Mayo in 1915 now glowers from a glass case in Belvedere College, Dublin, a memento of Fr Patrick Kennedy, the Jesuit ornithologist who taught there.
Occasional, non-breeding eagles were seen up to 1930, and a pair from the west coast of Scotland nested for a number of years on Fair Head, Co Antrim, in the 1950s. After that, while Aquila chrysaetos was still a rare visitor, its extinction as a resident Irish bird was complete.
Its restoration has long been a dream of naturalists, especially since Scotland's golden eagles have survived persecution, poison and pesticides to recover their numbers in the era of conservation. With almost 1,000 birds, Scotland has one of the more substantial eagle populations in Europe. Even so, the birds in south-west Scotland no longer rear enough young to make a natural recolonisation of Ireland likely in the near future: the number wandering across to Ulster has actually fallen in the past decade. This is why a plan to reintroduce eagles at Glenveagh National Park as a millennium project depends on chicks removed from wild eyries in the Highlands, Grampians and Mull, and released in Donegal over five years starting next June.
Reintroductions of such a highly-valued species have to meet a stringent set of international guidelines, and the project has taken a decade to develop. A study for the National Parks and Wildlife Service compared the amounts of grouse, hares and rabbits living in the home ranges of Scottish eagles to the prey available in Donegal. Kilo for kilo, the food supply seems to be ample. The banning of strychnine as a farm poison in 1991 has also dramatically reduced the risk of poisoning - the spread of buzzards into Donegal from Northern Ireland, and the proliferation of ravens are further evidence of that.
From 1995, the prospect of reintroducing eagles was taken up vigorously by the Irish Raptor Study Group and Birdwatch Ireland. A prime mover in the study group has been Lorcan O'Toole, who managed the red kite reintroduction projects in the Highlands and Central Scotland. The eagle programme is now a joint project between the voluntary groups and the NPWS at Glenveagh.
Two Scottish experts have given it significant support. Dr Jeff Watson, an authority on golden eagles and director of operations for Scottish Natural Heritage, and Roy Dennis, of the Highland Foundation for Wildlife, have both endorsed Glenveagh as an ideal location: the range of crags for nesting is unchanged, and big stretches of regenerating heather give the cover that prey species need.
Scottish goodwill is vital to the project. In his recent book on the eagle, the fruit of 20 years' study (The Golden Eagle, Poyser, 1997), Jeff Watson sees the bird's restoration to Ireland as a particular challenge. But the task of collecting 15 chicks a year for five years is, by itself, a huge investment of effort.
Scottish fieldworkers, voluntary but licensed, will take them separately from eyries in remote mountain areas. Each will come from a two-chick nest at about six to seven weeks - old enough to keep itself warm and to take food placed on a nest platform in a very large cage.
Once at Glenveagh, the young birds will be kept in their cages for a further five or six weeks, their food placed through a sleeve in the back wall by people they never see: "imprinting" on humans is avoided at all costs. Even after they fly, they will come to the roofs of the cages for food for several weeks, and then to a long-term dump of food nearby. Young eagles depend on their parents for food for as long as three months after leaving the nest.
The total of 75 chicks may seem a great many to rear and release, even over five years, but mortality is high in young birds. As many as 80 per cent of fledglings do not last the five years it takes to reach breeding age. A successful initial outcome would be three or four pairs of eagles, nesting between Muckish Mountain in the north to the Glendowan Mountains in the south.
The natural life-span for an eagle is about 20 years, but in Scotland a good many immature birds are still shot or poisoned, especially on or near moorland managed by grouse-shooting syndicates. This particular threat does not exist in Donegal, but sheep farmers may feel their own concerns about proximity to eagles.
Golden eagles will sometimes take very young lambs, mostly as carrion, sometimes alive. In Scotland this usually happens where ewes are left to lamb high on the hills and without protection. Irish hill farmers bring their ewes down to lamb. "Where there is sufficient natural prey for eagles," insists Jeff Watson, "the frequency of lamb-killing is very low indeed." Consultation with farmers around Glenveagh will begin this autumn, and John Marsh of the Irish Raptor Study Group suggests Scottish farmers with experience of eagles may be invited to Donegal to offer reassurance.
Even in the later 1800s, when Ireland's eagles were in severe decline, there were at least 60 nesting sites in Ireland, and Watson remains optimistic that, with a managed reintroduction and effective control of poisons, the birds could once again claim the skies from Donegal to Kerry.