A two-week festival celebrating Scotland's seaweed-eating sheep is being held in Orkney.

Around 3000 sheep live on North Ronaldsay, where they are farmed for their mutton and wool.

Visitors will help islanders round the sheep up for shearing - an event locally known as a pund - and learn how to repair the ancient stone wall separating the sheep from the rest of the island.

Festival organiser Kate Traill Price said: "The festival is utterly unique and offers volunteers the opportunity to work alongside our community in conserving our rare and iconic sheep."

Because of their unusual diet, the sheep are vulnerable to copper poisoning and have to be prevented from grazing on local farmland.

They are separated from the rest of the island by a drystone dyke that encircles the island but storms that batter the island each winter force the islanders to constantly repair the wall.

The festival's organisers said the work is a "continual challenge".

The event will run from July 25 to August 5.