The hen harrier is threatened with extinction in Britain and the special conservation programme, based in north Lancashire, may prove crucial to their survival.

Last year, just 11 pairs attempted to nest and breed across in the whole country.

Six of those pairs were in the Forest of Bowland in Lancashire as a result of the project.

Local cooperation

The harrier protection programme is being run by English Nature.

English Nature's Ian Carter said the co-operation of local gamekeepers and landowners had been crucial to the success of the scheme.

He added: "What we are trying to do is get to the bottom of why the hen harrier is so rare.

"It is a mystery as to why there are so few birds nesting and breeding because the climate in this country should allow it."

Hen harriers have been tagged in the Forest of Bowland and their progress observed by English Nature conservationists.