This drab, windowless concrete facade does not conceal an electricity substation, data servers, or a high security detention center. Instead, it is a factory farm for edible swiftlet swallow nests, the eponymous ingredient in traditional Chinese bird's nest soup.
The birds traditionally built their nests in the enormous limestone caves of Borneo, from where they were harvested by "skilled climbers using flimsy bamboo trellises." The nests, which are woven by the male of the species entirely from strands of saliva, dissolve in water to give a gelatinous texture to sweet or savory soups and are prized in Chinese cuisine for their reputed medicinal benefits.
For much of the 20th century, the market for the nests was limited to a wealthy few in Hong Kong, as Mao Zedong had condemned the soup as a "decadent luxury" in mainland China. Now, however, the BBC reports that a surge in demand "has forced prices up from about $400 a kilo (2.2 pounds, or the equivalent of about 120 nests) in the mid-1990s to $3,000 a kilo for the highest quality nests on today's market." The result is that custom built concrete birds' nest factories like the one showed above have spread across Malaysia, Thailand, Vietnam, and even Cambodia, towering above traditional one-story structures and transforming the urban landscape.
BBC reporter Joe Boyle visits Kumai, a small town at the southern tip of Indonesian Borneo, which he says has been completely taken over by the oversize birdhouses, becoming a "bird's nest soup factory town."
Kumai's human population is about 20,000. Its population of swiftlets—the tiny birds whose nests are so valuable to the Chinese—must be 10 times that number. They cover the sky, thrashing about and letting out screeches that are audible in every part of town.
"The Chinese started building birdhouses here about 10 years ago," says a local park ranger. "At first it was fine, but now it's taking over the whole town. The people don't have much of a say. Local politicians just let it happen."
The internal design of these bird's nest farms—or swiftlet hotels, as they are sometimes called— is fascinating: the buildings are intended to mimic caves, with a carefully spaced matrix of wooden rafters replacing the ledges and crannies of a cave ceiling, and detailed attention paid to internal temperature, humidity, and even sound. According to the BBC:
Bird farmers are still notoriously secretive about how they attract the animals, but part of the method appears to be playing recordings of the swiftlets' song.
Indeed, bird's nest farming seems to have become something of a boom industry across the region, with developers competing to attract investors with Balinese-themed "Swiftlet Paradise Resorts" and experts hawking "5 Star Swiftlet Chirp CDs". According to Wikipedia, Indonesia made $226 million in 2009 from the industry, which accounts for 0.5 percent of the country's GDP—equivalent to about a quarter of its fishing industry. The industrialization of edible bird's nest farming even has environmental benefits, an Oriental Bird Club representative told the BBC, as it reduces human disturbance in the more traditional cave habitats.
Images: (1) A typical swiftlet farm exterior, Thailand, photo by Alexander S. Heitkamp, via Wikipedia; (2) Bird's nests for sale in Chicago's Chinatown, priced at between $800 and $1,500 a box, photo by Maisnam, via Wikipedia (3) Detail of a swiftlet farm roof complete with loudspeaker, via Tirok Swiftlet Farm