A bird of prey threatened by human disturbance on Exmoor is to receive extra protection in an attempt to safeguard its nest sites.

Exmoor is thought to be the only place in the South West where merlins, just 25-30cm long, breed.

During the 1950s and 1960s, in common with other birds of prey, merlins suffered from the effects of pesticides as their traditional food supplies of small rodents became tainted.

Human persecution, habitat loss and increased disturbance may also be responsible, but overall the reasons for their decline are not fully understood.

Unfortunately the impact of vandalism or violence can't be discounted and the RSPB believes at least one pair failed to successfully produce any young last year due to human interference.

All wild birds are protected under the law and merlins are specially protected from disturbance when they are breeding.

The craggy heathland of Exmoor that is the merlins' breeding habitat

Anyone found guilty of ‘intentionally or recklessly’ interfering with a merlin nest faces a fine of up to £5,000 and/or six months in prison.

"We’re doing all we can to protect merlins on Exmoor," said Wildlife Crime Officer, PC Roger Jolliffe.

"It’s thought to be the most important site for the birds in the whole of southern England and we believe the birds are under threat.’

The RSPB, Exmoor National Park Authority and the National Trust will also keep a close eye on the Exmoor merlin population throughout the spring and summer, as well as being involved in the first thorough survey of the birds for five years.

"The aim of the survey is to determine the number of breeding pairs across the moor," said Helen Booker of the RSPB

"In the early 90s monitoring of Exmoor showed there were five breeding pairs, but by the time the last survey was carried out in 2000 it had fallen to just two pairs."

The survey is being largely paid for by the Exmoor National Park Authority, with the aim of finding the most important areas for the birds so they can be given the best possible protection in the future.

"As well as our own protection activities," said Helen. "We urge members of the public to be on the look out for any suspicious activity and to report it to the RSPB and the police."