Human health could have been put at risk after a red kite was found dead in a reservoir from lethal poison.
The Irish-bred bird was pulled from the Vartry water supply near Roundwood in Co Wicklow over two weeks ago after it died from eating contaminated meat bait.
Marc Ruddock, red kite project manager for the Golden Eagle Trust, said there was a potential for serious consequences for the water supplies.
"It was found in drinking water supplies. It is totally unacceptable. The bird has been thrown there or died there," he said.
"This is a highly toxic chemical - it doesn't bear thinking about. Anglers use the reservoir, dog walkers, and this water is for supplies for the south Dublin suburbs. Poison should not be in the lake in the first place."
The carcass of the bird was laden with alphachloralose, which should only be used to kill rats and mice, and was found a few hundred metres from homes and a pre-school.
Mr Ruddock said the bird was full of meat which had been covered with lethal doses of the poison.
"Alphachloralose is lethal to a human. Yes there is water treatment and purification but it should not have been in the water in the first place," he said.
It is the twelfth red kite to have died from poison.
A dog walker discovered the bird on September 3 and contacted Birdwatch Ireland who informed local National Parks and Wildlife Service staff.
The kite was only 14 months old and was one of a small number which have travelled north to the Roundwood area.
Jimmy Deenihan, Minister for the Arts, Heritage and the Gaeltacht, said the latest death was unacceptable and urged anyone with information on the misuse of the poison to contact authorities.
"The use of this type of poison is strictly limited to the eradication of mice and rats, and should at no time be used in the unacceptably reckless way it was," he said.