Golden Eagles from the Borders have played a major role in proving that the species can lay eggs at just three years old.
Normally, golden eagles breed for the first time from four to six years of age.
Only once before has a three-year-old eagle been confirmed as laying eggs, and that was in south-east Spain.
This new information about the breeding behaviour of golden eagles was discovered through a satellite tagging project run by the Highland Foundation for Wildlife, Scottish Natural Heritage (SNH), Natural Research and the RSPB.
Two satellite transmitters were attached to young golden eagles in Galloway and Strathspey in July 2010. Two young females laid eggs this year, at just three years old, having mated with older males in the Scottish Borders.
Roy Dennis, Director of the Foundation, said: “This is very exciting, as it is the first proof in Scotland that golden eagles can breed at three years.
“It shows that when they live in areas with plenty of food and little competition, golden eagles can breed at three years old.
“Unfortunately, the eggs did not hatch but that is not surprising for such young individuals.”
Golden Eagles, like many larger bird species, mate for life.
Some naturalists suspect that the so called ‘unusual mating systems’, i.e. the earlier mating, is a response to a period of population readjustment following persecution.
Females tend to lay four eggs, from which one or two young usually survive.
Professor Des Thompson of SNH, who chairs the group running the work, added: “Both areas where these young Scottish golden eagles have bred were previously identified as having several unoccupied territories.
“Previous research has pointed to a link between persecution and younger golden eagles managing to secure territories and attempting to breed.
“The shortage of older females may explain why such young birds have managed to breed.
“Provided the right conditions now prevail - being persecution free, good availability of prey, good weather, and appropriate habitat - then we hope that these birds will attempt to nest again next year and young will fledge.
“This would signal the start of an upturn in the fortunes of golden eagles in these areas.”
The golden eagle is the UK’s second largest bird of prey and has a wing span of around two metres.