A detailed 3D image of a bird's voice box has been created by scientists investigating how the animals sing.
Researchers in Denmark have modelled the tiny vocal organ of the zebra finch.
The study identified how the syrinx organ is adapted for rapid trills, even during flight.
According to the team, despite advances in understanding the neural control of birdsong, the physical ability is less well understood.
"Many great anatomists in the 19th Century have made absolutely wonderfully detailed drawings of the syrinx of many bird species," explained Dr Coen Elemans from the University of Southern Denmark, who led the study.
"However, now we have made a very high-resolution dataset in 3D that was not done before."
The research, published in the journal BMC Biology, focused on the zebra finch: a colourful songbird native to central Australia.
Dr Elemans' team achieved the detailed 3D model using high-resolution imaging techniques, including magnetic resonance imaging (MRI).
The science of song
Mammals produce sounds using their larynx, an organ at the top of the windpipe, but birds have evolved a different organ.
The syrinx is found where the windpipe forks to the lungs. In zebra finches this measures just 1cm from top to bottom.
Read on: http://www.bbc.co.uk/nature/20935932