Harsh weather conditions have dealt a blow to the breeding of red kite chicks.
Plans to increase the bird population hit a set-back when four of nine breeding pairs were unsuccessful due to storms in May.
Heavy winds blew nests from trees as they were being built and the birds had not yet laid eggs.
Plans to expand the population came after the reintroduction of the red kite to Northern Ireland in 2010, the first time in 200 years.
The five remaining pairs were successful however, with one nest found to have triplets - another first for Northern Ireland, according to the Royal Society for the Protection of Birds.
The RSPB will continue to monitor the birds and put emphasis on educating the public about kites, said Adam McClure, the society's new red kite monitoring and outreach officer.
"Staff and volunteers are pleased with the progress made this year and everyone we've spoken to about the kites' success this year has welcomed the news and had positive things to say about these magnificent birds," Mr McClure said.
"The local community, farmers and landowners are very protective and proud of their kites and without their help this project would not be possible. I would like to take this opportunity to thank them for their continued support as we enter our fourth year."