The bird was discovered by a Lisnaskea landowner and recovered by police on February 7. It had been dead for some time and was badly decomposed, but a  transmitter fixed to the bird to record its movements was recovered.

Given a chance it would have nested on one of the many islands on Lough Erne. The Golden Eagle Trust could give no cause of death, but did state that illegal poisoning has been the greatest mortality factor in Ireland. The GPS transmitter on the bird stopped transmitting in early December, but the Trust harboured hopes the bird was safe and sound as the transmitter would give intermittent signals due to low light levels.

They had hoped Fermanagh would be the first White Tail Sea Eagle (WTSE) territory in Northern Ireland and  with the location roughly half way between the Kerry release site and the most southerly breeding site of the Scottish population the possible first step towards a greater pan-Celtic WTSE population.

A spokesman for the Irish Wildlife Trust said: “Ingar was a male born in 2009 who had spent a lot of time around Lough Erne. It had been hoped that he was going to set up a territory on the lake and take a mate but sadly this is not to be.

“With a long life span and small reproductive output, every eagle is important in the reintroduction scheme and every loss a heavy, heavy blow.

“People on this island, north and south, need to unite to stamp out the persecution of all our wildlife, especially birds of prey,” she added.

 RSPB Fermanagh Area Manager Brad Robson told the Herald he was ‘very disappointed’ that the bird  had been found dead in Fermanagh. He explained that the eagle was a fixture in Fermanagh up until around 100 years ago, before they died out. In recent years the Golden Eagle Trust launched a project to bring birds such as the Golden Eagle and the White Tail Eagle back to Ireland again.

“It is a very sad story. We were getting pretty hopeful we would be able to breed Sea Eagles again in Fermanagh. The fact he was based in Fermanagh all summer showed he was finding food somewhere, it’s very disappointing.”

This is not the first high profile death of the rare bird in Ireland, as back in March 2014 one of the first white-tailed eagles to be successfully bred in the country was found dead in a Tipperary field, with 50 shotgun pellets in it.

Police have asked that anyone with information on the circumstances of the rare bird’s death to contact them on the 101 number, quoting reference 6467215.