A former military airfield is proving a haven for the skylark, whose numbers are in decline across much of Europe.
The RSPB says the UK's skylark population halved during the 1990s
The bird's population at St Davids airfield in Pembrokeshire has more than doubled since work began eight years ago to turn it into a hay meadow.
UK skylark numbers halved in the 1990s and continue to fall with the decline blamed on changes in farming.
Surveys at the airfield have found the number of breeding pairs has risen from 30 in 1998 to 65 this year.
The rise coincides with the Pembrokeshire Coast National Park Authority taking over the management of the land.
Conservation team leader Mike Howe said the number of breeding pairs had risen by 10 in the past year.
"This represents a huge increase in the population since the authority purchased the site and began to manage the grassland as traditional hay meadows, in partnership with a local farmer," he said.
"Since that time we have achieved organic status for the grassland."
The airfield, one of eight built in Pembrokeshire during WWII, was put on the market in the mid-1990s after the Ministry of Defence ruled it surplus to requirements.
According to the Royal Society for the Protection of Birds, skylark populations are in decline across much of northern and western Europe.
It said the main cause was thought to be a widespread switch from spring to autumn-sown cereals which had caused a fall in habitat for chicks, as well as the increased use of insecticides and weedkillers affecting their food source.
Mr Howe added: "Our work has shown how more traditional farming practices can benefit wildlife greatly.
"Our challenge is to find ways for farmers to return to this kind of management without compromising their incomes."