- Their little cup-like nests are made entirely from threads of saliva.
它们小巧的杯状燕窝完全由唾液丝筑建 - It takes more than 30 days to complete one.
每个燕窝得花上30多天才能完工 - The nests are very precious objects,
燕窝是非常珍贵的东西 - and not only for the birds.
不仅只是针对这些鸟而言 - For 500 years people have been harvesting the nests of cave swiftlets.
500年来 人们一直采集洞金丝燕的燕窝 - It's a very risky business.
这是一项非常危险的工作 - with virtually no safety equipment
事实上没有任何安全措施