The hogs are being killed to stop them eating eggs of rare birds which share the island, but campaigners want the animals moved to the mainland instead.

Charity, Advocates for Animals, said the killings were "totally outrageous".

Conservationists said bird numbers on the island have halved since the mid-1980s after the hedgehogs were first introduced to the islands in the 1970s.

Campaigners said they were going to stay on the island for six weeks to try and rescue as many as possible. So far on Monday, they said they had 15.

The birds in danger are some of the most important populations of waders in the country, and include the dunlin, redshank and oystercatcher.

The culling of the hedgehogs started last year, when 66 animals were killed. Scottish Natural Heritage (SNH) and RSPB Scotland say killing them is the only way to solve the problem.