Evidence suggests ospreys have bred in Ireland for the first time in more than 200 years.
The discovery was made at a confidential nest site in County Fermanagh, Ulster Wildlife has said.
A pair of birds have produced at least two, possibly three chicks, after returning to the same site since 2021.
The osprey is a medium-sized raptor that feeds primarily on fish and is usually found near bodies of water.
The naturally-established chicks were discovered by Giles Knight, environmental farming scheme advisor with Ulster Wildlife, who has been observing the breeding pair for the past three seasons.
Ospreys often nest in the same treetop for up to 20 years and are strongly faithful to both nest and mate.
Mr Knight said he had been keeping the news quiet for a long time to ensure the safety and welfare of the birds.
"You can imagine my excitement the moment that I saw three chicks and two adults this year," he said.
"It was a rub-your-eyes, once-in-a-lifetime moment; an absolute highlight of my 30-year wildlife career - like finding long-lost treasure.
"With at least two of the chicks fledging this season, this is a huge conservation success story and indicates a healthy wetland ecosystem with plenty of suitable habitat and fish to bring this apex predator back to our skies and plunging into the Fermanagh lakelands."
The osprey is listed on the amber list of UK birds of conservation concern, this is due to long-term population decline.
They are a protected species in Northern Ireland.
Ospreys are thought to have become extinct as a breeding bird in Ireland in the late 18th century, but they are often spotted on migration to and from sub-Saharan Africa.
In May, the Irish government announced plans to reintroduce the bird with between 50 and 70 chicks to be brought from Norway over a five-year period.
It is hoped these chicks will establish a free-ranging population that eventually breeds in Ireland.
Liaison has been ongoing around the undisclosed Fermanagh site and the public has been urged to avoid disturbing the birds.
Mr Knight added: "Now these birds are back in Ireland and breeding successfully, it is critical that they are left in peace so their numbers can continue to grow by returning year on year to breed.
"We believe and hope that this could be the start of a raptor dynasty."