Variations in the songs of different groups of corn buntings in the Western Isles have helped scientists to chart the decline in numbers of the birds.
By studying the pattern of male birds' songs, researchers can identify different groups of buntings.
|Photo: Nigel Blake|
In the past males could find enough mates within their own groups.
But Aberystwyth University scientists have found the dialect groups are beginning to mix together suggesting males are flying further to find mates.
RSPB Scotland said a survey of corn buntings suggested there could be as few as 76 territorial males in the Western Isles.
Since last year, the charity has been providing crofters with a mix of whole and crushed barley to improve the birds' survival in winter.
Jamie Boyle, of RSPB Scotland, said: "Corn buntings are great wee birds - known to generations of crofters as gealag-bhuachair.
More information on the corn bunting (Emberiza calandra):