THEY have a haunting cry that often provide an eerie backdrop in Bronte novels.

But the call of the curlew may be lost from Scotland forever as their eggs are being wiped out by predators such as foxes and crow.

According to new research, the number of curlews has dropped by more than 60 per cent over the last 20 years and faces extinction in some areas.

The losses are the single highest of any terrestrial breeding bird in Scotland and have been attributed to changing land use and predation of eggs and chicks.

But the future of Europe's largest wading bird has been given hope after a study identified the main factors behind its dramatic decline.

The British Trust for Ornithology (BTO) report blames a loss of habitat as the bird breeds most in areas of semi-natural grassland and moorland and there are also small and declining populations in areas of extensive arable farming.

The study also found curlew numbers were lower in areas with most foxes and crows with worst hit Scotland, Wales and Northern Ireland.

The curlew nests on the ground, leaving its chicks especially vulnerable to predators.

Its haunting song was used to introduce BBC Radio's first natural history programme, The Naturalist, in 1946.

Curlew nests and chicks are vulnerable to predators, raising the question of how their management might be used as part of wider conservation efforts, to protect favoured sites and improve breeding habitats.

The report said: "Here in the UK, we have seen dramatic declines in Curlew populations over recent decades, resulting in the species being proposed as the UK's most important bird conservation priority.

"If we are to halt and reverse these declines then we first need to understand which threats this iconic species is facing."

The study was conducted by the BTO as part of the Breeding Bird Survey (BBS) programme, using this information to determine how curlew populations have changed in different regions and habitats.

Identifying the problems the curlew is facing is the first important step in helping to change the fortunes of the iconic wader species.

Ieuan Evans, head of membership and volunteer engagement at the BTO, said: "The study, focused on the rapidly declining curlew, highlights how important understanding the reasons for declining numbers can be in efforts to halt deterioration of vulnerable species.

"The UK holds almost a third of the global breeding population of curlew and this population is declining fast.

"Declines have been greatest in Scotland, Wales and Northern Ireland, and in Ireland the breeding range has contracted by a massive 78 per cent.

"The recent and dramatic declines have resulted in the species being proposed as the UK's most pressing bird conservation priority.

"If we are to reverse the fate of this iconic species then we need to understand the threats it faces."