The number of red squirrels being spotted at an Aberdeenshire castle is on the rise, according to new figures.

The endangered species was found in 54% of all areas at Crathes Castle in Aberdeenshire in 2011, a major increase from 26% in 2005.

The National Trust for Scotland (NTS) has also discovered a "dramatic decrease" in the number of grey squirrel sightings at the same site.

Only 9% of areas surveyed were found to have grey squirrels, compared with 39% in 2005.

Fiona Milne, senior ranger, said: "The north-east is a stronghold for this threatened species, so we are really pleased with the positive results at Crathes.

"We have been working hard to encourage reds to thrive here. The results of our latest monitoring show that we are making good progress which is excellent news."

The news comes six months after the NTS launched their red squirrel conservation plan, which includes installation of warning signs for motorists and a greater focus on grey squirrel control.