Scientists believe that dozens of young guillemot sea birds found dead recently on the east coast died from starvation.
The public began reporting to a bird flu hotline and BirdWatch Ireland that birds were being found dead along the coast from Monday.
The first discovery was made at Killiney beach, Co Dublin, where four birds were found, and later that day 12 birds were found dead at Dundalk, Co Louth.
According to Niall Hatch of BirdWatch Ireland, the number of dead birds being reported raised concerns over possible pollution at sea.
"We were on to the Wildlife Service, the Department of Agriculture and the Coast Guard and no pollution was uncovered."
He said between 12 and 17 dead birds turned up in Arklow yesterday as scientists continued their investigation.
"When the birds were identified as guillemots, it became clear they were all juvenile birds. There were no adults.
"Having ruled out pollution, and because the birds had no oil on their feathers, the scientists discovered the birds had died from hunger."
Mr Hatch said it was possible the young birds were from second broods and did not have the strength to survive the very tough life the guillemot leads.
"They need plumage and they need it fast to survive the diving they have to do to catch fish when they feed far out at sea."