A ninth red kite has been found dead from illegal poisoning, park rangers have said.
The breeding female bird, which had been nesting on a farm near Redcross, Co Wicklow, was found near Brittas Bay late last year.
It is the latest red kite killed by poison in the county, while there have been similar deaths in Kildare and a suspected poisoning in Limerick since the re-introduction project began in 2007.
Dr Marc Ruddock, Red Kite project manager, said it was a demoralising loss.
"These birds are specialist scavengers, that's why they are finding these food sources which are sadly poisoned. They are designed to clean up the countryside," he said.
"These illegal actions jeopardise local biodiversity and the economically important and deserved reputation and profile natural Wicklow cherishes."
The bird, known as Blue Purple G, was one of the first young kites brought from Wales and released in July 2007. She had found a mate and was known to have successfully bred and raised three young at Redcross.
Dr Ruddock called for anyone with information on poisonings to contact local National Parks and Wildlife Service rangers and gardaí to help identify and confront individuals repeatedly and illegally poisoning wildlife.
Penalties for illegally poisoning birds of prey can be up to €5,000 or 12 years in prison.
Park rangers said a search of land and door-to-door inquiries in Redcross and Brittas failed to find any other birds, animals or bait items.
The kite was the third poisoned with alphachloralose in the last five months, a chemical which can only legally be used in controlled dosages to kill mice.
Jimmy Deenihan, Minister for Arts, Heritage and the Gaeltacht, said irresponsible and illegal use of poison baits has killed pets as well as the birds of prey.
"I would appeal to people to act responsibly when it comes to implementing pest control measures, and they should never be at the cost of causing death to birds of prey and other wildlife," he said.
"The irresponsible use of poison baits has also killed numerous working dogs and domestic pets, in some cases where families had just taken their dog for a walk in the woods."
Meanwhile, in the Lusk area of north Dublin, the NPWS is dealing with a spate of secondary poisonings of red kites caused by the legal control or rats and mice with chemical poison.
Seven birds have died after eating legally poisoned rodents.