Consumers’ growing taste for nests made from swiftlet spittle gives ‘birdhouse’ a whole new meaning, but could it mean lasting damage to Vietnam’s ecosystem? By Lien Hoang. Photo by Lee Starnes.

After Uyen Vien injured his arm in a 2008 motorbike crash, he stemmed the lingering pain with a trusted remedy: the saliva of birds.

Tropical swiftlets use their spittle to build nests, and Vien used one of those nests to make a medicinal soup.

“I had a bowl once a day, and after a week, I felt better,” he says.

Seeing those effective results, he decided to construct a house outside Ho Chi Minh City where the birds could build their nests. By harvesting those nests and charging as much as $2,000 per kilogram, many swiftlet ‘farmers’ across Vietnam can make a fortune. It’s part of a larger trend around Asia, where consumers are becoming increasingly wealthy and increasingly attracted to such luxuries as bird’s nest soup.

But could the growing demand hurt the regional ecosystem?

Gathorne Cranbrook, co-author of the 2002 book Swiftlets of Borneo, says the domesticated birds (which live in buildings) are “genetically different” from their wild cousins (which live in caves). The birds can navigate in the dark and are very behaviour-driven, so those born in houses will grow up to seek out similar places in which to build their own nests.

As competition for food increases, the farmed swiftlets risk shutting out the wild ones, as well as other varieties of swifts whose slobbery secretions aren’t so coveted. In some ways this is a zero-sum game because of the so-called “carrying capacity”, or the maximum number of birds that the local environment can support.

“It is a disadvantage to the wild birds,” Cranbrook, a leading expert on swiftlets, says in a telephone interview from his home in England.


A centuries-old trade

Bird saliva is not a new delicacy in Asia. In the 16th century, and perhaps earlier, people were spelunking across the region to feed the lively nest trade. Cranbrook says Dutch merchants noticed this when they arrived at the time, especially in the tropical climates where the swiftlets thrive.

Caving could be a deadly profession; there are still reports to this day that people have fallen from ladders during harvests. In Vietnam, much of the industry officially centres on Nha Trang.

But that has changed in recent years, as skyrocketing demand pushed companies and individuals to set up brick-and-mortar homes for the swiftlets. Some build small dwellings just for the birds, while others simply add on attics to their existing homes to welcome feathered tenants. The taste for bird’s nest especially saw a boom in the 1980s.

“It used to be for kings and the rich,” says local trader Tran Anh Trong. “But now it’s popular.”

Shops that sell bird’s nest (to yen) have exploded around Ho Chi Minh City to cater to domestic customers, as well as those from Hong Kong, Singapore and China. Countries from Indonesia to Malaysia breed swiftlets as well. Bloomberg reported in August that demand is so great that it “is spawning a cottage industry that has attracted investment from VinaCapital Group Ltd, the nation’s largest fund manager, and helping mint new millionaires.”

Vietnamese who do buy the nests often do so as gifts to elder relatives. People consume them after undergoing surgery or giving birth. They’re believed to improve everything from digestion and libido to asthma and aging. Their actual healing properties are up for debate. Even Trong says it might just be in people’s heads.

“Psychology is very important,” he says.

Some Vietnamese don’t seem to mind whether the benefits can be proved, saying they feel better after drinking bird’s nest soup, and that’s proof enough. Still, a VnExpress article in January cited associate professor Ngo Dang Nghia as saying recent research suggests the benefits are real.

He said the drooly concoction helps generate cells so that ailing bodies recover more quickly, supports firm bone development, keeps skin looking young, and strengthens the immune system against viruses.

Unlike bear bile and rhino horn, bird’s nests comprise a largely legal trade because they don’t seem to harm the creatures involved.

But Jean-Francois Voisin, who co-wrote The White Nest Swiftlet and the Black Nest Swiftlet, recommends wild nests over farmed ones because they’re larger and more sustainable. He also warns against the indiscriminate use of pesticides, which harm the insect populations that feed swiftlets.

“Another problem with farm swiftlet[s] could be genetic pollution,” Voisin writes by email. He explains that interbreeding could result in a species that is less adaptive to nature, less productive, and more susceptible to disease. More field research needs to be done, but the bird’s nest industry is large enough to pose unintended consequences that won’t be realised until decades down the line.

Dried bird’s nest pictured from Pho Yen, 86-88 Ham Nghi Street, District 1 in Ho Chi Minh City.