A small bird that makes its home out of its saliva, which is used to make bird's nest soup.
Swiftlets are important in some cultures for making a special kind of soup.
Examples:
The swiftlet makes its nest out of its spit.
People use swiftlet nests to make soup.
The swiftlet is a small bird.
I saw a swiftlet flying in the sky.
The swiftlet's nest is very special and expensive.
The swiftlet's nest is very important in some places.