High above the rooftops of Shanxi province, the sky sings with a haunting, multi-toned drone that ebbs and flows with the synchronized banking of a flock of pigeons. This distinct acoustic tradition — once the ambient soundtrack of ancient Chinese cities — is surviving into the 21st century thanks to a handful of dedicated elderly craftsmen and a surprising digital e-commerce boom.

At his workbench in the Taigu district of Jinzhong, 70-year-old master artisan He Ganglin meticulously carves a dried gourd. When finished, his creation will be a translucent, feather-light instrument weighing a mere 7 grams, yet when attached to a bird in flight, it will produce a resonant, melodious chord.

Pigeon whistles, or ge shao as they are known in Chinese, are a unique traditional folk handicraft in China, boasting a history stretching back over a thousand years. These whistles, also called pigeon bells, are attached to the tails of pigeons.

As the birds fly, the wind rushing through the whistles' opening causes the air inside to vibrate and resonate, creating sounds often described as "aerial symphonies".

"The pigeon whistle is more than just a toy or a handicraft," He said, his wrinkled face etched with pride. "It embodies the regional culture of Shanxi, the symbolism of peace, and the spirit of perseverance of traditional artisans."

Historical records indicate that pigeon whistles appeared as early as the Northern Song Dynasty (960-1127). Shanxi, situated at the crossroads between the Central Plains and the grasslands, was a strategic border area.

Pigeons were used to deliver messages, and the whistles identified pigeons, sounded border alerts and guided homeward-bound birds.