January 8, 2013 – A multinational team of researchers made a significant step forward in trying to understand how birds produce their beautiful songs. "We used cutting-edge 3D imaging techniques to understand the complicated structure of the vocal organ of songbirds, the syrinx", says Dr. Coen Elemans, from the University of Southern Denmark, the senior author on the study. Elemans and his colleagues are publishing their findings January 8, 2013 in BioMed Central's open access journal BMC Biology.
Communicating with sounds is central to the life of most animals and they use it to signal their identity, what species they belong to, to attract partners, to avoid predators, and to teach their young. "Songbirds in particular excel at vocal communication", says Elemans. Many song notes are superfast and very reproducible, even while the bird is in constant motion. "Just imagine an orchestra musician playing his instrument while performing a dance. How do birds do this?", he wonders.
There are several intriguing similarities between how juvenile songbirds imitate their parents to learn their songs and how human infants imitate to learn how to speak. Therefore the vocal learning abilities of songbirds have been of great interest. "We know quite a bit about how the songbird brain codes and decodes songs and how young songbirds learn to imitate the songs of their adult fathers. But we know very little about the instrument itself, the vocal organ called syrinx ", explains Elemans.
While mammals make sound with their larynx, birds have evolved a unique structure that is located where the windpipe forks to the lungs. It has two pairs of vocal cords and songbirds can sing with two notes at the same time. To reveal the detailed structure of the syrinx, the team mapped it with high-resolution imaging techniques such as high-field magnetic resonance imaging (MRI) and micro-computed tomography (μCT). They created 3D interactive PDF models showing the muscles, cartilages, and bones of the syrinx in unparalleled detail. "We show how the syrinx is adapted for superfast trills and how it can be stabilized while the bird moves. Also we emphasize how several muscles may work together to control for example the pitch or volume of the sound produced ", he adds.
Elemans concludes by saying that "the results lay down the foundation for our understanding of how songbirds can undertake such complex vocal acrobatics, so we can unravel the mystery of how songbirds produce some of nature's most inspiring sound compositions."