Red squirrels have seen a surge in numbers in Scotland’s north east and stabilised nationwide, according to new figures.

Research carried out by conservation workers shows the rodents’ population has stopped shrinking across the country.

The most positive results from Scotland’s Red Squirrels 2017 survey revealed numbers have seen a “significant” boost around Aberdeen.

They are also starting to appear in areas they have long abandoned, according to researchers.

Conservation officer Mary-Anne Collis said: “In the Central Lowlands, red squirrels are holding their ground and as a result we’ve started to see them in areas where they haven’t been seen for a long time.

“This is particularly noticeable to the south and east of Loch Lomond and the Trossachs National Park, which is now predominantly a red-only zone.

“If it wasn’t for our fantastic volunteers that brave the unpredictable spring weather to help us with these surveys then we wouldn’t be able to see the positive impact that our conservation work is having.”

Grey squirrels, which were introduced to Britain from North America in the 19th century, out-compete red squirrels for resources.

They can also carry squirrelpox, a virus that does not harm them but is deadly to reds.

Since 2011, Saving Scotland’s Red Squirrels has been monitoring populations in the parts of the country where the rodents are most under threat from non-native greys.

Numbers are surveyed using feeder boxes placed in the same areas of woodland each spring.

When a squirrel visits a feeder box, a sticky tab collects some of its hair, which can then be identified under a microscope.

Despite most areas successfully maintaining population levels, southern parts of Scotland saw mixed results.

The survey produced no positive results in Berwickshire, where reds are now very rarely seen.

Project manager Dr Mel Tonkin said: “Unfortunately red squirrel numbers have continued to fall in parts of the Scottish Borders, especially since the arrival in Berwickshire of the deadly Squirrelpox virus from south of the border in 2011.

“In Dumfries and Galloway, red squirrels continue to do well, but are threatened by increasing records of grey squirrels which appear to be spreading into Nithsdale from the east and north.

“It is vital that the work we do here is stepped up to make sure these red squirrel populations remain healthy.”