‘Aphrodisiac’ nests under threat

HOI An is a beautiful town near the mouth of Vietnam’s Thu Bon River.

Among its temples and ornate ‘tube’ houses is a building with a large hand-painted sign over the entrance. The inscription is in Vietnamese, but an English translation is provided underneath: ‘Department of Managing and Gathering Swallows Nests’, it reads. The nests are on Cham Island which is 21km out in the South China Sea east of the town and the bird which makes them isn’t a swallow but a swift.

The little cup-like structures about the size of a hen’s egg are attached to the walls of caves. They are made from the bird’s saliva which solidifies as it dries. The ‘edible nest swiftlet’ makes its nest entirely from spit. Other swiftlet species incorporate some feathers in their structures.

When the birds begin breeding in the spring, local people converge on the caves, as they have done for centuries. Bamboo scaffolding is erected and rope walkways are attached to the walls of the caverns. Climbing up to the colonies and collecting nests of the ‘salangane’ is a hazardous business. The harvest is exported to China, mainly Hong Kong, and to the United States. There, chefs dissolve the material in water to form a paste which is the principal ingredient of a gourmet delicacy known as ‘bird’s nest soup’, a bowl of which could set you back up to €80 in a swanky restaurant. With nests fetching between €1,500 and €2,000 per kilo, swiftlet spit is the world’s most expensive animal product.

It has a rather bland taste, so why do people crave this soup? Emperor Ming Mang ruled Vietnam from 1820 to 1841. An autocrat and control freak, he resisted western encroachment on his country and curtailed the activities of proselytising Catholic missionaries. Christian monogamy did not appeal to Ming, who fathered 107 children with his wives and concubines.

His extraordinary fertility, the Vietnamese claim, was made possible through eating swiftlet saliva. Modern gourmets, likewise, hope that the soup will confer amorous vigour on them.

Scientific analysis can find nothing in swiftlet spit of any value as an aphrodisiac. My visit to the Department of Managing and Gathering Swallows Nests was not a success. The swift caves on Cham Island are off-limits to visitors and a request that an eco-journalist from Ireland, working on a ‘story’, be allowed to visit cut no ice.

The island has a military installation and was completely off-limits to visitors until recently. Now, a fishing village there can be visited, but anyone approaching the swiftlet caves is likely to be shot. Like our own swift, the little aerial insect feeders are highly adapted for flight and almost helpless when they alight. Clinging to rock surfaces with their sharp little claws, they are vulnerable to hawks and falcons.

The walls and roofs of large dark caves are the only places where safe nesting is possible. Forming large colonies gives added protection; some swiftlet breeding sites hold hundreds of thousands of nests. Cave walls seldom have nooks and crannies where eggs would be safe, so nests have to be constructed. Swiftlets can’t land to collect nesting material so the birds use spit. Like Superglue, it hardens when in contact with air and the nest becomes anchored to the rock face.

With several million nests being harvested each year in Southeast Asia, there are claims that the bird-nest soup industry threatens the swiftlet’s survival. Sites like those in Cham Island are jealously guarded, but poaching is said to be widespread elsewhere.

The entrepreneurial Vietnamese are unlikely to kill a goose which lays such valuable golden eggs.