In the past, swiftlet nests from Vietnam were seen as the highest quality on the market; today, Vietnam is opening up, and I bet that the swiftlets there will quickly disappear.
過去越南會安、歸仁燕窩被市場視為最高級的「貢燕」；如今越南開放，我看當地金絲燕也很快就會沒有了。