A floruishing breed of bird of prey has become a “victim of their own success” after being targeted by gamekeepers, according to an animal charity.

The RSPB suspects that up to four buzzards have been shot in the past 12 months in the county according to their latest report published this month.

However animal charity investigators said the figures were just “the tip of the iceberg” with prosecutions notoriously difficult to achieve and requiring detailed intelligence and covert operations.

The attacks on birds of prey nationwide is also set to rob Sussex of the pleasure of hen harriers, which face extinction.

The RSPB Birdcrime report 2012 includes two buzzards that were found dead in East Sussex in March last year, which both appeared to have been shot.

In July, a post-mortem on a third buzzard found dead in Pulborough revealed the bird had been shot.

There was a further unconfirmed buzzard shooting in East Sussex in 2012 plus two other unconfirmed shootings of birds of prey in West Sussex.

The common buzzard, which is a protected species, was a rare sight in the county three decades ago, but over recent years their numbers have grown with up to 300.

Mark Thomas, a senior investigations officer with the charity, said successful prosecutions can take up to three years to achieve and were difficult because most occurred on private land when no one else was around.

He added: “Hen harriers winter in Sussex on the coast, especially around Pulborough Brooks, and there should be 300 breeding pairs in the country.

“We didn’t have any breeding pairs this year and they are going to be extinct in England.

“Bird of prey crimes are carried out by people who have shooting interests and who want to get rid of birds of prey who will attack grouse and moor hens.

“Buzzards are doing very well and are appearing in places they had not before and people are targeting to get rid of them.

“Birds of prey persecution is not going away. It has been around for a very long time and even in these enlightened times, it still lives on in areas.”