An increasingly bitter war is taking place between bird lovers in County Down's Mourne Mountains.
The BBC has learned that the sky above the Silent Valley is the scene of a battle pitting peregrine falcon conservationists against racing pigeon enthusiasts.
Peregrine falcon numbers in the Mournes have plummeted
The peregrine falcon, which is protected by law, is one of the world's fastest hunters and when the bird of prey swoops on a flock of pigeons, the results are devestating.
However, the falcons are now falling prey to an equally deadly human hunter.
Conservationists believe a "hit man" has been hired to shoot the birds of prey and they are pointing the finger at the racing pigeon world.
A racing flightpath goes through the Mournes attracting hundreds of birds every weeekend.
Pigeon fancier John Millar said while he would not condone the shooting of the falcons, some other pigeon owners might be tempted.
"The peregrines are waiting for them coming. They know their line of flight and they just dive into the middle of that flock and they are decimated.
"The peregrine falcon is a protected bird, but it is quite possible that some people could take the law into their own hands, which we would not encourage them to do.
"If somebody has lost valuable pigeons, they will try and remedy it," Mr Millar said.
Jim Wells said several peregrines had been killed
Jim Wells, of the Raptor Study Group, said he believed several falcons had been killed.
"We believe that a hit man has been hired to shoot as many peregrines as possible in south Down and south Armagh.
"We believe that he may have already killed 30 birds. That is having a devastating impact on the population of this area," Mr Wells said.
When adult birds are killed their chicks are left to starve to death.
Another conservationist said he believed he had prevented the killing of the last surviving pair of breeding peregrines in the Mournes.
"I noticed on the cliffs above the nest site a man in camouflage gear holding a shotgun," he said.
"He was basically camouflaging himself completely and lying down in the heather above the nest preparing to shoot these birds."
The conservationist, who did not want to be identified, said that when he challenged the man he ran away.
Peregrine numbers, once healthy, have crashed in the Mournes, and conservationists are now guarding the only remaining nest with chicks.