A new study has found that the way birds sing and talk to each other is no different from how humans do so.
Published in the journal Nature Communications, research from a team out of University of Southern Denmark and other academic institutions showed that while birds and humans sound differently when singing, the exact same mechanisms are at play - and evolved separately - to make their vocal cords work and produce sound.
This mechanism that drives human speech and singing, called the myoelastic-aerodynamic theory (MEAD), has been known in science for more than six decades now.
"We have now shown that birds use the exact same mechanism to make vocalizations," said lead study author and associate professor of biology Dr. Coen Elemans, who added that MEAD might even be a prevalent mechanism among land vertebrates.
The team studied[pdf] six bird species coming from five avian groups, with the largest - the ostrich - weighing 200 kilograms, and the smallest - the zebra finch - weighing only 15 grams.
All the birds studied were revealed to have been using the MEAD mechanism found in humans. The researchers explored the subjects by filming the birds' sound production using high-speed cameras.
In the larynx or voice box of humans, air coming from the lungs is pushed past the vocal cords, which in turn begin to move back and forth in a sideway motion. Sound pulses are produced when the larynx opens and closes with every oscillation, letting the air flow start and stop.
Co-author and voice expert Dr. Jan Švec from Czech Republic's Palacky University - who called their findings a "very surprising and fascinating" discovery - said that the oscillations take place from around 100 times per second during normal speech to among the highest possible notes in opera, about 1,400 times per second.
"[This is] an F6 in Mozart's 'Die Zauberflöte,'" said Dr. Švec.
Birds, on the other hand, make sounds not with their larynx but with their syrinx, buried deep in the breast cavity and therefore very difficult to study.
The findings also shed light on the neural workings governing vocal learning in both humans and birds. Both are not born with the capacity to speak or sing, but learn by listening to others or through vocal imitation learning.
With songbirds as a good reference to study the human voice and its neurological conditions, the team's research in their vocal production is aimed by Dr. Elemans to be used in analyzing human vocal creation.
Photo: Rodney Campbell | Flickr
