The presence of pine martens in Northern Ireland has almost doubled, according to a new report.

The elusive native mammal had been greatly reduced due to habitat loss and persecution in the 19th century.

However, a new survey report by Ulster Wildlife has shown significant pine marten expansion across all counties since 2017

A 2022 survey of pine martens, red squirrels, and grey squirrels – carried out across 218 woodlands, found that pine martens were present in almost double the number of sites compared to the previous survey in 2017.

The latest survey findings indicate a remarkable turnaround, with pine martens now found throughout all six counties, marking a significant expansion beyond their traditional stronghold in Co Fermanagh.

The pine marten expansion is also hoped to be a boost for red squirrels.

Ulster Wildlife said the number of woodlands surveyed with red squirrels present remains comparable to 2017, suggesting that the population is holding steady at a landscape-scale.

The red squirrel population was decimated by the introduction of grey squirrels from North America in 1911, out competing their smaller cousins for food and carrying the deadly Squirrelpox virus, to which greys are immune.

While the survey showed that the presence of greys had declined slightly since 2017, the most notable decrease was in woodlands surveyed in Co Tyrone, with Co Fermanagh continuing to maintain its status as a sanctuary free from grey squirrels.

Ross McIlwrath, priority species officer with Ulster Wildlife, said pine martens recovery is hoped to boost the red squirrel population.

“It’s fantastic to see pine martens spreading and returning to areas where they haven’t been seen for many years,” he said.

“This recovery will hopefully boost our much-loved red squirrel populations as we are seeing that in areas with a strong pine marten presence, greys are retracting. Red squirrels have adapted to live alongside these native predators, unlike their non-native counterparts.

“However, we cannot get complacent as red squirrels are still in trouble from grey squirrels and habitat destruction. Many reds squirrels have disappeared from small areas of woodlands and urban areas, and have become increasingly isolated and fragmented.

“We need to continue to work with partners, landowners and local conservation groups to control the spread of greys, create a more connected landscape to allow reds to spread and recover, and ensure continued long-term monitoring of these three species.

“A huge thank you to everyone that took part in the survey, especially the volunteer red squirrel groups across Northern Ireland.”

Ulster Wildlife is encouraging the public to contribute to conservation efforts by reporting their sightings of all three species at ulsterwildlife.org/report-sightings

The presence-absence survey was carried out using camera traps and squirrel feeders throughout 2022 by Ulster Wildlife and 15 participating partners, including local red squirrel groups, National Trust, Mourne Heritage Trust, Colin Glen Trust, Belfast Hills Partnership, Black Mountain rewilding Project, ABC Council and Wildfowl and Wetlands Trust.

The survey was supported by the Department of Agriculture, Environment and Rural Affairs (DAERA) and the Garfield Weston Foundation.