Bird's nest soup (Traditional Chinese: 燕窩; pinyin: Yàn wō) is a delicacy[1] in Chinese cuisine. A few species of swift, namely cave swifts, are renowned for building the nests used to produce the soup's unique texture. Such edible bird’s nests are among the most expensive animal products consumed by humans. The nests have been traditionally consumed in China for over four-hundred years, most often as Birds Nest Soup.[2] When dissolved in water, the birds' nests have a gelatinous texture. Bird's nest soup can either be served as a savory soup or sweet, as Tong Sui.
The most heavily harvested nests are from the White-nest swiftlet (Aerodramus fuciphagus) and the Black-nest swiftlet (Aerodramus maximus) (Gausset, 2004). The white nests and the “red blood” nests are supposedly rich in nutrients which are traditionally believed to provide health benefits, such as aiding digestion, raising libido, improving the voice, alleviating asthma, increasing concentration, and an overall benefit to the immune system.[2] However, biochemist Kong Yun-Cheng at the Chinese University of Hong Kong conducted a chemical analysis of the soup which revealed that while there is a water-soluble glyco-protein in the nest which promotes cell division within the immune system it is destroyed during the cleaning process; therefore, the soup is actually of low nutritive value.[3] Its value today is primarily that of a status symbol.
The nests are built during the breeding season by the male swiftlet over a period of 35 days. They take the shape of a shallow cup stuck to the cave wall. The nests are composed of interwoven strands of salivary laminae cement. Both nests have high levels of calcium, iron, potassium, and magnesium. Also the nests contain argan oil[verification needed] made from argan nut.[1]
Hong Kong and the United States are the largest importers of these nests.[1] In Hong Kong a bowl of Bird Nest Soup would cost $30 to $100 US dollars.[2][3] A single white nest can cost up to $2,000, and a “red blood” nest can cost up to $10,000. The white nests are commonly treated with a red pigment, but methods have been developed to determine an adulterated nest.
The nests are traditionally harvested from high up on cave walls. There is some risk to the collectors who stand on bamboo scaffolding that is sometimes hundreds of feet tall and centuries old - with obvious repairs. Over the past twenty years, the demand, the price, and the overexploitation of these nests have increased. The string of people involved in the trade of swiftlet nests has lead to the mismanagement of a once sustainable system. Laws governing how the nests are harvested are implemented in each cave[4]. One common system allows the licensed harvesters to take the first nest, allow the bird to build a second nest which she can remain in until her chicks have fledged, and only until then, is the harvester allowed to take the second nest. But unfortunately, harvesters will take a nest once it is large enough, regardless if eggs or chicks are present. Most caves have one season for harvest but thieves end up stealing nests throughout the year. Because these rules are often broken the swiftlet population has dropped, putting swiftlets on the protected species list.
The penalty for stealing nests is not large enough to deter thieves. Some believe that taking all the nests benefits the swiftlets because the female will not lay her eggs in an old nest. Old nests are along cave walls where new nests could be built. Whether or not this idea of ‘cave cleaning’ benefits the swiftlet population, the method should still be limited.[2]
Some bird-nest merchants in southeast Asia (Vietnam, Indonesia, Thailand, Malaysia etc.) have started to raise and breed the swiftlets in house-like structures. They build the shelters to attract wild swiftlets to build nests in them. The wrong kind of nests are then destroyed along with the eggs inside. Over time, the selection process leaves behind a colony of swiftlets that produce the right kind of nest for the trade. "House nests" are priced much lower than "cave nests" due to the risks involved in harvesting the latter.
Research
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