Fears were raised last night over the recovery of one of East Anglia's most threatened birds, despite figures showing that its numbers were growing.The red-listed stone curlew, which is one of the country's top conservation priorities, is experiencing a revival in the Brecks after suffering from years of intensive farming practices.

Fears were raised last night over the recovery of one of East Anglia's most threatened birds, despite figures showing that its numbers were growing.

The red-listed stone curlew, which is one of the country's top conservation priorities, is experiencing a revival in the Brecks after suffering from years of intensive farming practices.

However, the RSPB and Natural England warned that the recovery of the migratory bird may be reversed unless measures to protect them from development and to create suitable habitats are not implemented quickly.

New figures show that a population count within the stone curlew's Brecks stronghold found 217 pairs this summer- an increase of 11 pairs compared to 2007. There were also 13 pairs in north Norfolk and eight in east Suffolk.

But the survey also revealed a dramatic drop in the number of young birds being fledged - only 123 chicks were raised - which has been blamed on a combination of the wet weather and the scrapping of set-aside farmland.

Officials from the RSPB and Natural England said they were concerned about the “significant decrease” in stone curlew fledglings - the lowest since 1988 - but the wildlife organisations were working hard to get farmers to form nest plots on their land as part of a new higher- level stewardship scheme.

Simon Tonkin, the RSPB's farm-land conservation officer, said he feared the numbers of the ground-nesting bird could decline again if it has another poor breeding season.

“Although the population is increasing, stone curlews are still a fragile species and their future is by no means certain. We need to ensure that they are helped through complementary farming practices, which Brecks farmers have a great record of doing, and through protection against increasing development pressures.

“In the last year, the RSPB has helped farmers, on over 5,000ha of farmland in the Brecks, access funds through agri-environment schemes. We are keen to help as many as possible access these funds to help stone curlews and other declining farmland birds,” he said.

Almost two-thirds of the stone curlew UK population nest in the Brecks area of Norfolk and Suffolk between March and October before flying to warmer climes in the winter. But fears have been raised about the end of set-aside schemes, the reduction in sugar beet farming, and the difficulty in getting enough farmers to sign up to new wildlife-friendly initiatives.

Pete Brotherton, head of biodiversity for Natural England, said: “The recovery of the stone curlew is testament to those farmers and landowners who manage their land with the needs of this bird and other wildlife in mind. However, we must remain vigilant to ensure that this scarce and enigmatic bird thrives in future, particularly in the face of increasing pressure on our farmed landscape.”