Baby birds which have lost their parents are being played CDs of the dawn chorus to teach them to sing.

The RSPCA is using the odd method after tests revealed it helped birds reared in captivity cope better when released into the wild.

A CD recording of the dawn chorus is played to the chicks, which would normally have learned from their parents, twice a day.

A spokesman for the charity says it helps them become good singers which helps them survive back in the wild with males using it to defend territory and find a mate.

The report looked at the findings of 158 previous studies to reach general conclusions about birdsong.