Ten protected birds of prey have been confirmed poisoned across the Irish Republic in recent weeks.
The birds included a golden eagle, as well as two red kites, two white-tailed eagles, three buzzards and a peregrine falcon.
One of the red kites had been released in Northern Ireland and was found dead in County Kildare.
The birds died after eating meat baits laced with pesticides, one of which is illegal in Ireland.
Two red kites and the peregrine were found dead in County Wicklow, the third red kite in Kildare, a golden eagle in County Leitrim, and buzzards in west Waterford, east Cork and County Donegal.
Within the last few weeks two white-tailed eagles were found dead near Beaufort, County Kerry.
Both eagles were said to be in excellent condition and had been surviving well in the wild for two or three years.
An investigation is being carried out by the Department of Agriculture and the Garda.
"The loss of a further two white-tailed eagles at this time is devastating," said Dr Allan Mee, manager of the White-tailed Eagle Reintroduction Project in Kerry.
"The older male could have been one of the first birds to breed in the wild in Ireland in over 100 years had it survived. Indiscriminate poisoning is literally killing our chances of re-establishing a population here," he added.
Fifty-five of the eagles have been released in Kerry since 2007. Thirteen of them have now been found dead, seven of them confirmed poisoned. Two white-tailed eagles were among the poisoned birds