Photo: Getty Images/Arun Roisri. Good enough to eat: an edible-nest swiftlet sitting on a fragment of its nest
A massive demand for its nests might sound as though it would spell trouble for any wild bird. Yet, as Tony Tilford explains, one Asian species of swift has actually flourished in the wake of intensive farming methods to increase supplies of one very popular food…
IT MUST have been during the 1960s that I first heard of the harvesting of birds’ nests for soup. David Attenborough’s BBC TV programme of the vast limestone Niah Caves in Borneo showed local village people climbing to the top of precarious bamboo towers to remove the swifts’ nests from the cave roof.
How times have changed. The market for these unusual birds’ nests has increased beyond belief and it has now spawned a thriving industry throughout southern Asia. These nests are not only highly prized in Chinese culture, they are now one of the most highly priced animal products eaten by humans. Only this month the cheaper white nests are being sold in Chinese food and medicine shops in Indonesia at IDR 1,800,000 per 45g (1½oz). That presently equates to £2,800 per kg! The rarer red nests, from birds with a different diet, are even more expensive.
The bird’s nest soup tradition goes back beyond 300 years. By all accounts, the result is a deliciously sweet or savoury soup of high nutritional value. The nests, which consist of strands of sticky saliva that has dried into a glutinous mass, contain high levels of calcium, iron, potassium and magnesium.
Edible nests are harvested mainly from the edible-nest swiftlet (Aerodramus fuciphagus) known locally as the walet. Today, the traditional collecting from the limestone caves has been all but abandoned and replaced by more easily accessible methods. Thirty to 40 years ago, it was noticed that the edible-nest swiftlets throughout southern Asia were entering abandoned or vacant buildings and building their nests inside. In Bali, I recollect, this was soon made the most of and swiftlets were attracted into the small “lumbung” buildings used for storing rice. Once in, the door was closed and the lumbung moved close to a more exploitable site. Today, in many places, it is common to see disused buildings, once occupied as shops, houses or even industrial buildings, turned over to throngs of nesting swiftlets.
Like bats, but with a clicking sound that can be heard by the human ear, the edible-nest swiftlet uses echolocation to navigate its way through the dark intricate caves or buildings. Their clicking calls rebound from walls and ceilings like radar to allow them to identify their position with accuracy.
On my recent visit to Mataram on Lombok Island, I was surprised to see large areas of buildings abandoned to swiftlet colonies, but also newly constructed multistorey buildings with the special purpose of attracting more to nest. These structures are kept cool by flooding the flat roofs with pools of water and made even more attractive by playing recorded swiftlet calls through loudspeakers positioned inside and at their entrances. It must be a really good business, because it now plays an important part in urban and rural life and is often featured in magazines and TV. Even the magazines carry advertisements for the world-famed loudspeakers that are now specially manufactured for the walet industry.
The business has now spread throughout South-East Asia, through Malaysia, Thailand, Sumatra and Borneo, all along the Indonesian Archipelago and southwards towards Australia. It has become a significant contributor to the economies of those countries; as an example, estimates of the business in Indonesia now account for 0.5 per cent of the Indonesian GDP.
Perhaps 50 years ago, we could have assumed that the harvesting of nests from their traditional caves would have adversely affected their populations, and it may have been so then. Today, the picture is certainly different with the birds advancing their territories into areas previously unoccupied, particularly the suburbs of cities and even into occupied houses. Modern nest farming and harvesting techniques have allowed the species to flourish with a significant increase in the swiftlet population.
Human intervention for business purposes has inadvertently contributed to species conservation. The pressure has been removed from the natural limestone cave habitats and the birds are once again free to live and breed there without human disturbance.
- Next week, Tony suggests a similar large-scale help effort to revive our population of swifts here in the UK.
Expert photographer Tony Tilford is an international author covering a variety of subjects including aviculture, bird field guides and travel guides.
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