Why is it called a swan song?

Related questions

1. Is a swan song real?
2. What does a swan symbolize?
3. Are swans aggressive?
4. Are swans intelligent?
5. Do swans die when their mate dies?
6. Are Black Swans real?
7. What else does Bebe Rexha song?
8. Do Swans mate with their siblings?
9. Is The Stand by Stephen King scary?
10. Are swans dangerous?

Tags

1. #during
2. #refers
3. #beautiful
4. #alternatively
5. #lifetime
6. #phrase
7. #before
8. #swans
9. #ancient
10. #having
11. #musical
12. #cygnus
13. #death
14. #silent
15. #their
16. #belief