Battle lines have been drawn over fresh signs of the advance of grey squirrels from north Angus into the Aberdeenshire stronghold of their native red cousins.
Non-native greys pose a deadly threat to the protected reds through the squirrelpox virus.
A number of grey squirrels have recently been found north of the River North Esk in areas including Marykirk, St Cyrus and Benholm.
Their creep up the Mearns coast has rung alarm bells among conservationists working to protect the native species.
Report sightings
Saving Scotland’s Red Squirrels is appealing for people to report sightings of both red and grey squirrels online.
The group fears that without urgent action, Mearns red squirrel populations are at risk.
The project is also looking for volunteers in the area to support its vital conservation work.
North east monitoring officer, Sarah Woodfin said: “Grey squirrels moving north from Angus into Aberdeenshire are a serious threat to local red squirrels, as well as the core Scottish population in the Highlands.
“The recent reports from the Mearns are worrying.
“Grey squirrels threaten red squirrels through competition for resources.
Squirrelpox
“Most worryingly, they could also potentially bring the deadly squirrelpox virus, which isn’t currently present in Aberdeenshire, with them.
“This virus doesn’t harm grey squirrels but it is deadly for reds.
“It would be devastating for Scotland’s squirrels if squirrelpox is allowed to spread into the north of the country,” she said.
Volunteers
“There are a number of ways that people can help.
“We need to recruit a number of volunteers to support our important work to protect red squirrels in the Mearns.
“We also want people living in the area to be on the lookout for grey squirrels in their gardens and in local parks and woodlands.
“All sightings of both red and grey squirrels are invaluable and can be reported to us at scottishsquirrels.org.uk.”
Since 2009, Saving Scotland’s Red Squirrels has been working in the north east to eradicate an ‘island’ population of grey squirrels
It was introduced in the 1970s and is isolated from the rest of the Scottish population.
Once widespread in Aberdeenshire along the rivers Dee and Don, this population of grey squirrels is now largely contained within Aberdeen’s city limits and red squirrels are increasingly seen in the city’s parks and gardens.