Wildlife experts are warning people not to feed seagulls.
Niall Hatch of Birdwatch Ireland says herring gulls have learned to associate humans with food and this is causing problems.
Residents in parts of North County Dublin have complained the birds are becoming more aggressive, and are demanding action.
Some parents are afraid to let their children play outside in case they get attacked by seagulls.
There are now 5,000 breeding gull pairs in North Fingal, who will produce 20,000 chicks by the early summer.
There are calls for the council to undertake a cull, but the herring gull is a protected species.
Mr Hatch says while there does appear to be an oversupply in parts of Dublin, a cull is not the answer.
"It really does come down to the behaviour, not just of the gulls but of the people," he said.
"What's happened is that some of these gulls have learned to associate human beings with food and that is a problem.
"It's not good when these birds expect to be fed. We really do advise people not to feed these gulls."