A body that took over regulation of EU protected bird sanctuaries in Northern Ireland after Brexit is launching an investigation into a Stormont department's management of them.
The Office of Environmental Protection will examine whether there have been breaches of environmental law governing 16 so-called Special Protection Areas (SPA) across Northern Ireland.
It includes Lough Neagh, which was heavily polluted last summer.
It is the biggest inland lake in Ireland and Britain and an important wintering ground for a host of different bird species, including Whooper Swans that visit every year.
"Populations of wild birds continue to decline across Northern Ireland, with recent studies placing a quarter of birds found on the island of Ireland on the Birds of Conservation Concern Red List," the Office for Environmental Protection said.
"Rathlin Island, the Antrim Hills, Strangford Lough and Lough Beg and Lough Neagh are some examples of SPAs, with the latter being the largest SPA in Northern Ireland."
The OEP will begin simultaneous investigations into SPA management in other parts of the UK. In Northern Ireland it will look at why previous reviews into the legally designated sites have not been completed.
"SPAs play a key role nationally and internationally in protecting populations of wild birds that are currently in regrettable decline.
"Our investigation will seek to establish whether the recommendations of previous SPA reviews, such as one that was published in 2001, have been fully implemented and if not, the reasons why not," said Natalie Prosser chief executive of the OEP.
"The background to our investigation is that recommendations from another review carried out between 2015 and 2017 have yet to be published. Another step in that review, which will include classifications of new SPAs and the adaptation of existing SPAs, has yet to begin."
The investigation will seek to establish if sufficient work has been done to protect the various sites across Northern Ireland.
The OEP investigation will focus on Stormont's Department of Agriculture and Environment DAERA, which has responsibility for the SPA sites.
