The ability to sing is crucial for males of most species as it declares their territory to rivals and plays an important role in attracting a mate. Because birds are taught to sing by their parents, being raised in captivity can leave the orphans at a serious disadvantage.
RSPCA officers introduced the singing lessons after examining 158 previous studies on songbirds. They concluded that the ability to sing was hardwired into birds' brains, but to master the art they needed to listen to other birds of the same species. Birds reared in isolation sometimes developed abnormal songs that harmed their ability to attract females, the study found.
"The majority of bird species benefit from being played birdsong. They listen to it and it helps them become good singers, which will in turn help them to survive when they are released," said Tim Thomas, an RSPCA wildlife officer.
Baby blackbirds taught to sing by the charity this year will be radio-tagged to investigate whether the recordings help rehabilitate the birds in the wild.
The charity receives about 4,500 fledglings during the months of April to August, accounting for roughly a third of the animals it cares for.