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My quest to understand bird’s nest soup

My quest to understand the appeal of bird’s nest soup

A serving of bird’s nest soup can sell for £80, but many people fail to understand the allure of eating a nest made from swiftlets’ saliva. Edward Posnett traces the origin of the dish, meeting the climbers and moguls who harvest and trade it

A serving of bird’s nest soup can sell for £80, but many people fail to understand the allure of eating a nest made from swiftlets’ saliva. Edward Posnett traces the origin of the dish, meeting the climbers and moguls who harvest and trade it

Edward Posnett | November 22nd 2019

It was not in a restaurant that I first tried one of China’s finest delicacies, bird’s nest soup. It was in the office of a nest “dealer” in the Malaysian city of Johor Bahru. Dr Tan Boon Siong usually shipped his nests across the Straits of Johor to wealthy ethnic Chinese Singaporeans, but he offered to set one aside for me. Dressed in a white lab coat and a hair net, he delicately removed the dish’s key ingredient from a small plastic box and held it up for me to inspect. It looked nothing like the nests I used to see in the English countryside when I was growing up – the threaded grass cup of a robin’s home or the muddy mass of a swallow’s. Brittle to the touch, the miniature white crust could have passed for a prawn cracker, but when I raised it to the light I saw that the nest was made of countless, fine white strands that were as translucent as gelatin. Tan took the crust and dropped it into a pot of boiling water. The nest softened, then dissolved, a bird’s work undone. He poured it into two white mugs and offered me one. “It’s like milk,” he said.

Tan’s nest once belonged to a swiftlet, a small bird native to caves in Southeast Asia. It takes this creature some 30 days to build its nest. It starts by retching and chewing, drawing strands of mucus from enlarged salivary glands below its tongue. The bird then threads these strands across a cave wall. The saliva hardens when it’s exposed to air, forming a shallow half-cup nest within which the bird can lay its eggs. Other kinds of swift use twigs or vegetation to build their nests, but the remarkable thing about the swiftlet is that it crafts its home entirely from itself, using saliva and sometimes feathers.

Since at least the 14th century these nests have been popular in China and are usually boiled in a broth to make soup. Swiftlet nests have been compared to caviar, petit fours, foie gras and even scones. Chinese emperors seem to have had a particular weakness for nest-eating and today the dish retains the aura of an imperial delicacy. No one knows for certain how or why the fashion caught on. Some claim that Zheng He, who led China’s great explorations overseas in the 15th century, brought bird’s nests back from his voyages in Southeast Asia. Hard evidence for this story is lacking, but it has nevertheless helped to turn swiftlet nests into symbols of Chinese nautical prowess and strength.

Such tales have helped maintain the value and status of bird’s nests as a luxury. Today Tan offers 30g of nests for around £130 ($170), enough for about three servings of soup. Nests are also treated as an elixir. Claims of their health benefits go back centuries. Many people in China believe that bird’s nests are an antidote to various conditions ranging from the common cold to skin disorders. Tan, a Chinese-Malaysian businessman, claims that his own mother had been cured of cancer by eating bird’s nests. He now eats bird’s nest soup every night. “That is why I am 60 years old and still look young,” he said. 

I’d read about the history of swiftlets’ nests, their supposed magical properties and their place in Chinese culture. Yet I was reluctant to put one in my own mouth, mixing my own saliva with that of a bird. Most natural products retain something of their original function when they are put to a new use: nestled in a duvet, eiderdown provides us with warmth; a glass of milk offers us nutrition. But eat a nest and you are devouring what was once a bird’s refuge.

Many people in ethnic Chinese communities around the world continue to enjoy nests as a delicacy, but most other people dislike the idea of eating a bird’s home. Studies outside China have not been able to confirm their apparently curative properties. For me, the bird’s nest has come to represent an enduring symbol of difference between cultures. I could try to make sense of the different facets of Chinese life, from the workings of its Communist Party to its writing system, but the bird’s nest somehow seemed impossible to decode. Could I overcome the gap between this “fouled crescentic cup”, as one British ornithologist described it, and its esteemed place in Chinese culture as the “caviar of the East”? 

A portion of bird’s nest soup Caviar of the East or tasteless broth?

I decided to trace the nests back to their origin. I travelled to one of the largest caves in Southeast Asia, the Great Cave in Niah, Sarawak in Malaysian Borneo. Often compared to a cathedral, the Great Cave is home to thousands of swiftlets that pour out of its mouth every morning to feed, forming clouds of black snowflakes. This has been one of the great centres of nest production since the 19th century. Swiftlets often nest in the most inaccessible parts of limestone caves, well beyond the reach of pythons, carnivorous insects and most human hands. 

Retrieving them requires a huge amount of skill, patience and risk, as I learned when shadowing one of Niah’s great harvesters, Haji Nuar, a short, stocky man better known by the name “Spider-Man”. For three decades Nuar has explored the caves around Niah, scraping swiftlet saliva from their walls and growing rich off their proceeds. He oversees the harvest from a hut in a small side cave, sleeping among insects, bats and birds, and he survives on a diet of mostly tinned food. He also eats the occasional nest, of course: “That is why I have such good skin,” Nuar explained. 

Within a side cave Nuar had erected a series of wooden poles and ladders that allow him to access its highest and most perilous chambers. He offered to take me to see the nests up close, but I politely declined. Just staring at his workplace gave me a sense of vertigo and unease. Perhaps here, I reflected, lay the secret to the value of these nests – not in their taste, nutritional value or curative properties, but in their story. When you eat bird’s nest soup, not only are you consuming the labour of a bird, but also that of the expert climbers who risk their lives to scale cave walls. But that theory soon fell flat when I learned that most nests on sale today – including those offered by Tan – do not come from caves. Most modern harvesters rely on an entirely different method, one which requires technology and money rather than muscle.

Swiftlets nest deep in limestone caves like this one, the Goumantong cave in Malaysia Going deep

In the 1990s rising incomes in China prompted a boom in demand for swiftlet saliva. Much like televisions or washing machines, nests became status symbols for China’s new middle class. Caves throughout Southeast Asia were ransacked, swiftlet populations plummeted and many climbers found their skills redundant. Faced with declining wild stocks, Indonesian business people instead started attracting swiftlets into “bird hives”, man-made tower blocks or apartments that imitate the conditions of caves and provide birds with lodging in exchange for their valuable produce. These new harvesters couldn’t be more different from Nuar. Most comfortable in collared shirts and Italian leather shoes, they specialise in the vagaries of the Chinese luxury market, pricing models, security systems for bird’s nest houses and electronic birdsong, which they use to lure swiftlets. 

Perhaps the most successful is Dr Boedi Mranata, an Indonesian biologist. A soft-spoken man with glasses, Mranata has the air of an academic but for the last three decades he has remained perched on the top of the nest “industry”, exporting tonnes of nests to ethnic Chinese around the world. Known by his associates as the “King of Bird’s Nests”, he presides over an empire of bird houses that stretch from Java to Kalimantan in Borneo. I visited one of Mranata’s houses in Java with Gathorne Gathorne-Hardy, a swiftlet specialist and ornithologist from Britain. After driving for a couple of hours from our base in Jakarta, we reached a plot of land covered by coconut and guava trees, an island of green away from the concrete city. At the heart of the plot lay Mranata’s creation, a brutalist tower block about seven storeys tall. It resembled a huge pillbox or bunker that would shoot out swiftlets from an opening at its top. Around its base was a small channel of water, a defensive moat, designed to deter insects or rodents. 

Mranata stood outside his tower and welcomed us with his arms outstretched. He stepped over the miniature moat, opened the metal door to the tower and invited us into his lair. We were greeted by warm, moist air and the sound of birdsong, played from sets of electronic speakers above us. Gummed against wooden beams were hundreds of nests stuffed full of baby birds, dark black against the whiteness of swiftlet saliva. Mranata beckoned us over to one of the beams and placed his finger inside a white nest, in which a swiftlet chick was huddled. He began to whisper gently to the birds. Mranata explained that one of his houses could reap somewhere between 200kg to 400kg of nests for every two months of harvesting. By selling 1kg of the nests for $1,000 dollars, Mranata can make $200,000 from a house every 60 days. “It’s a small bank,” he said.  

Recently-harvested swiftlet nests Soaring prices 

As I walked through Mranata’s fortress, I was struck by how far technology had transformed the earlier harvests. Today’s nests are different to those once eaten in imperial banquets. Although they seem to embody wildness, they are produced by semi-domesticated birds that are now genetically distinct from their cave-dwelling ancestors. Since the 1990s houses have been built throughout Southeast Asia, the value of the trade in swiftlet nests has soared and is estimated to be worth billions of dollars. Farmed birds have fanned out all over the region, yet the number of wild birds in caves continue to plummet in places such as Niah.

Not that their decline would be noticed by anyone shopping for these nests in a large city.  If you visit centres of global capital such as Beijing, London, New York or San Francisco, there is plenty of swiftlet saliva to go around. The new challenge for modern harvesters is to convince those who have not grown up with the tradition to see the allure of eating nests. In Kuala Lumpur, I met the chief executive of a bird’s nest firm, Swiftlet Eco Park, who intended to list his company on the New York Stock Exchange and flood the North American market with swiftlet saliva. Mranata’s daughter, Ariani, was also hopeful of a breakthrough. “When there is a proper paper that comes out that says [there are health benefits], I’m sure it is going to be commercialised,” she enthused. “It’s going to be turned into pills, canned food and jams.”

Despite her enthusiasm, and after months in caves and bird houses, I was no closer to understanding the attraction of these objects. Yet perhaps, in an increasingly globalised world, it is to be celebrated that a nest can still be mysterious. This thought came to me on the last phase of my journey when, in Tan’s office in Johor Bahru, I finally raised a mug of dissolved nest to my lips. After swilling the liquid around my mouth like a sip of wine, I realised a simple truth that I did not have the courage to say out loud: the nest was entirely tasteless.

This piece is adapted from the author Edward Posnett’s book, “Harvest”