An outbreak of bird flu which has seen hundreds of dead seabirds washed ashore is now threatening the gannet colony on Sceilg Bheag off the Kerry coast.
It is one of Europe's biggest gannet colonies - and the virus appears to be spreading rapidly there.
There have now been 142 confirmed cases, but the Department of Agriculture says the infection is now widespread among seabirds.
There are more than 35,000 breeding pairs of gannets on Sceilg Bheag and if avian flu continues to spread there it could have a devastating impact on a colony of global importance.
Sceilg boatman Gearóid Moran said: "Every year you'll see a few dead birds in the water, but this year there's an awful lot more dead birds.
"Even up on the rocks, on the cliffs, you can see there are dead birds lying down and they're barely moving and they're wings are just flapping gently - they're on the way out."
Gannets and other species have already been hit heard off Britain, but the dense nature of the Sceilg colony is of concern allowing for rapid transmission of the virus.
Counts from earlier this year found that from a flock of 40,000 barnacle geese in north west England up to 10% died, according to Martin Enright from Birdwatch Ireland.
"That's a considerable number of deaths in any colony," he said.
The National Parks and Wildlife Service is conducting coastal surveys, while the Department of Agriculture is monitoring the outbreak.
The conservation group has called for collection and disposal of the carcasses, while people and pets are advised to keep their distance from dead birds.