Bird flu has been confirmed in a number of dead birds found on Rathlin Island, which is home to Northern Ireland’s largest seabird colony.
They were discovered at the island’s main harbour, Church Bay, earlier this week and removed for testing.
The RSPB says there are now suspected cases at the colony near its West Light Seabird Centre on the island.
Bird flu has also been confirmed at two other locations since the start of June.
There have been positive test results on birds found at Lough Erne, County Fermanagh, and in Bangor, County Down.
Gemma Daly, a veterinary officer with the Department of Agriculture, Environment and Rural Affairs (Daera), said there were 50 dead guillemots reported on Rathlin, which is where the positive test samples came from.