Songbirds 'sing from hymn sheet'

By Pallab Ghosh
Science correspondent, BBC News

Songbirds like zebra finches can give clues to how humans learn to speak

Songbirds learn to sing from a hymn sheet in their head, according to a new study.

Swiss researchers have identified a region of the Zebra Finch brain which they believe has an internal recording of how the birds ought to be singing.

A separate region seems to enable the birds to identify mistakes in their songs, they wrote in Nature journal.

The research could also shed light on how humans learn to speak, according to scientists from Zurich University.

They monitored the electrical activity of cells in the zebra finches brains which are associated with listening.

They did this as the birds were singing, and while the birds were listening to recordings of other zebra finches.

Hymn sheet

Some neurons were constantly active, as if the finches were listening to a recording in their brain.

Other cells became active when the birds made mistakes, or when they heard recordings of songs which featured disturbances or disruptions.

It is these cells that enable the birds to learn from their errors, according to lead author Professor Richard Hahnloser, of the University of Zurich.

He said: "This is a proof of concept that birds do actually listen to their own songs, and they do seem to be comparing it to something that they expect, or would like to hear.

"So these neurons could give us a clue of how the birds learn their songs, with reference to some song that they've previously stored in their brain".

The authors believe their research could also shed light on how humans learn to speak.

It has long been assumed that, like songbirds, humans learn complex vocal patterns by first listening to their speech and then comparing it to patterns stored in the brain.

But very little is known about the neural mechanisms involved.

Our closest relatives, the great apes, do not speak, so songbirds may provide a better model to observe how speech develops.

Zebra finches appear to recognise their own mistakes and those of others

Clock chimes

Meanwhile, in a separate study in the same journal, scientists used zebra finches to identify the "clock" that controls the timing of complex vocal behaviour in songbirds.

Both birdsong and human speech require precisely timed execution. But the specific brain circuits involved in the timing were unknown.

Researchers Michael Long and Michale Fee attempted to identify these "clocks" by cooling down the cells in different areas of the finches' brain.

Cooling the temperature in a region known as the high vocal centre (HVC) slowed the finches' songs down by up to 45%.

But the cooling did not affect the sequence of notes sung. This suggests the "clock" that regulates the timing of birdsong lies in the HVC.

Writing in the journal Nature, the team from Massachusetts Institute of Technology suggests that its technique could help identify the "clocks" for other complex behaviours.