Up to a dozen days of grouse shooting could be on the cards this year at the Bolton Abbey Estate.

The estate’s agent, Ben Heyes, said it was too early to tell whether there would be enough birds on the Duke of Devonshire’s purple heather moorland to stage the prestigious shoots, but hopes were high that there would be an improvement on last year.

Mr Heyes was speaking on the eve of yesterday’s Glorious 12th, marking the start of the shooting season which runs until December.

Grouse shooting on the 14,000-acre moorland estate resumed last year in the wake of a two-year shooting ban imposed due to a blight on the grouse population caused by parasitic worms.

Mr Heyes said numbers of red grouse were growing, but the extent of the improvement would only be revealed once a thorough bird count had been carried out with the help of highly trained dogs.

“We have got a few more grouse than in the recent past and there will be a little more shooting as the numbers gradually improve, but to what extent is the 64 thousand dollar question,” said Mr Heyes. “We have got a provisional programme with shoots booked for a dozen days, but we will have to walk the moors and flush the birds out and then we will have a better idea. We are still a long way off the numbers of grouse recorded during our best years.”

Mr Heyes said the grouse shooting would provide a welcome boost to the local economy with patrons paying between £30 and £150 per brace. The shoots also provide local employment with the more expensive events typically involving 25 individuals on the beating line, eight gamekeepers, nine loaders with further people needed to pick up the birds.

Mr Heyes said it was important to generate income for the shoots to help preserve the heather moorland which provides crucial breeding and feeding grounds for many of Britain’s rarest and declining bird species.

Elsewhere, Keighley Moor is not expected to produce many grouse, said a spokesman, and adjoining Emmott Moor, where there had been a devastating fire, was unlikely to have a good season.