Cages by Sylvia Torti

Author:Sylvia Torti
Language: eng
Format: epub
Publisher: Schaffner Press
Published: 2017-08-31T04:00:00+00:00

“The bird’s syrinx is like your larynx,” he told them. “When you exhale to speak, air is pushed from your lungs past flaps of skin in your larynx. The flaps vibrate and create waves of sound.”

“Here, Rebecca,” he said, placing his fingers softly against the front of her throat. “Pretend you’re in a doctor’s office. Say ‘aaaa.’”

She voiced “aaaa.” He lifted her hand from the table and exchanged her fingers for his. “Do you feel the buzz?” She nodded. The other students began to “aaaa” as well.

“The buzz comes when the vocal folds partly cover the opening in the larynx called the glottis. Now make the sound lower. Now higher.”

The students did as they were told.

“For lower frequencies, the flaps are further apart, vibrating more slowly. For higher frequencies, they come close together and move very fast.”

Whether in humans or birds, every exhalation was a potential sound. The folds pulled in and vibrated. Or they did not. But unlike in humans, in birds the right and left sides of the syrinx could be controlled separately by nerves coming from left and right sides of the brain. David could snip a bird’s left syringeal nerve and instantly, the low frequency sounds were gone and the bird’s song shifted higher.

“From the syrinx,” he continued, “waves of air travel up and out the beak.” He drew a blue line for air from the syrinx, up through the trachea and out the beak. “Beaks function something like our mouth, tongue and lips to filter out certain frequencies, to create resonance.” He noticed that Rebecca had straightened herself in her chair. “Beaks held wide open enhance high pitched sounds. When the beak is more closed, the sounds are lower.”

His ultimate goal was larger. It was true that he wanted to know how a bird sang, how the impulse to make sound had been organized throughout millions of years of evolution, how air was pushed past the syrinx making it vibrate, but those were only the technical parts of the story, the relatively easy things to know, the questions he could pose in grant proposals and be sure, at least up until this year, to secure funding for. These were the questions that had kept his laboratory running for the last decade, kept the students busy with projects, but not the ones that kept him awake at night, not the ones that had drawn him to biology.

As a teenager he had walked a daily loop around his neighborhood. Behind the row of new houses, there was a field of undeveloped land bordered by a copse of trees, a small stream and a pond, the relics of a farmer’s property. He knew what he was likely to see and hear, knew at which spots the chipmunks and squirrels would rattle at him, which thrushes would flush from the ground as he approached. But some days there were surprises. Once he came upon the pond and found a purple gallinule standing still, one bright yellow leg bent, the other in the water.

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