Scientists studying the process of birds singing have concluded that the birds carry the equivalent of a hymn sheet in their minds.
The studies have been conducted on the brains of Zebra Finch. Studying electrical impulses being transmitted between neurons, scientists believe they have identified a specific region containing the recording of what the song should sound like. This region remains electrically active even when the bird is listening to another bird sing.
A separate region indicates the fidelity with which the bird is reproducing the sound at any particular moment. It seems to be electrically activated only when the bird's song is disrupted or it makes a mistake. This is part of the bird's learning mechanism. Scientists see this system as a proof of concept for the belief that an animal is listening to itself singing as part of the process of refining it.
Such experimentation has value for understanding how humans learn speech and song. Studying birds is preferring to studying primates in this context since they have more developed mechanisms for verbal communication.