Stone curlews have been fitted with high-tech tags so their movements can be monitored.

The crow-sized birds with large, bright yellow eyes, were close to becoming extinct as breeding birds in the UK 30 years ago. Thanks to conservation efforts, around 400 pairs of stone-curlews now breed in the UK each year, more than half of them in eastern England.

By learning more about them, researchers hope to help landowners create the conditions stone-curlews need for nesting and feeding, in order to ultimately achieve a sustainable stone-curlew population in the UK.

The study is part of the PhD research of Rob Hawkes, the RSPB's heathland officer, and is being supported by organisations including the RSPB Centre for Conservation Science, the University of East Anglia, Natural England and the Ground Disturbance project.

Mr Hawkes said: 'It's incredibly exciting, not just because we're doing something that hasn't been done before, but because we're learning new things about how the birds behave that just haven't been possible to study before, and this will improve our understanding of what we need to do to help stone-curlews.

'We knew that stone-curlews are mainly nocturnal and forage at night. When they have eggs the adults take it in turns to sit on the nest, which gives the 'off duty' bird the chance to go in search of a meal. Using the GPS tags we have discovered individual birds travelling much further from their nest to find food than had been known previously, suggesting the birds are prepared to travel a substantial distance to reach a favoured feeding site.'

Thirty years ago, most of stone curlews' natural breeding habitat - grass-heaths and downs - had been lost, and a high proportion of birds took instead to nesting on farmland, where they were vulnerable to farm machinery.

Thanks to the intensive efforts of farmers, land managers, gamekeepers and conservation organisations to protect vulnerable nests and create safe nesting plots, the number of stone-curlews breeding in the UK has more than doubled since 1985.

Robert Gough has farmed in the Breckland region of East Anglia – one of the stone-curlew's UK strongholds – all his life.

'Like lots of farmers in the Brecks, we've been working with the RSPB and others for many years to help stone-curlews nesting on our farm, and it has been very gratifying to see the positive impact these efforts have had on their numbers.,' he said.

'This year we've had five pairs of stone-curlews on the seven specially-created nesting plots we have on the farm as part of our agri-environment agreement. Because the nests were on safe plots and not in amongst crops we didn't need to intervene or interrupt farming operations to avoid damaging them.

'The more we can encourage the birds to nest where they are safe the better – for them and for us – and that means creating safe places for them, on farmland and elsewhere.'