A new scientific study suggests hedgehogs are having a devastating impact on seabirds in the Outer Hebrides.

The research has been seized on by the Royal Society for the Protection of Birds to back its calls for a change in the law.

The bird welfare charity wants to see tougher controls placed on the introduction of new animals where they have previously been absent.

It has long been suspected that hedgehogs ate large quantities of seabirds' eggs on the grassland, known as Machers, where the birds nest.

Several thousand hedgehogs

Now the proof has come in the shape of an experiment carried out on South Uist and published in the scientific Journal of Applied Ecology.

By excluding hedgehogs from two fenced plots it was found that wading birds like the dunlin, lapwing, redshank and snipe had two and a half times greater breeding success.

The hedgehog problem dates back to the 1970s when half a dozen were introduced. Now there is thought to be several thousand.

Further experiments will determine whether the hedgehogs can be removed to save the birds.

But now the RSPB's is seeking changes in the law to prevent a repetition of the problem.