The notion of a swan's final song is rooted in folklore and mythology, particularly among European cultures. Swans have long been associated with beauty, grace, and purity. In many myths and stories, swans are connected with prophecy and musical ability.
The idea that swans produce a melodious and haunting song before their death derives from the behavior of certain swan species, particularly the mute swan. These swans can sometimes produce a resonant and melancholic sound, especially during the last few weeks of their life. This mournful quality of the swan's call may have inspired the legend of the swansong.
Over time, the term "swansong" has been used metaphorically to describe a person's last major achievement or significant contribution before retirement, death, or a major change in their life. It suggests a powerful and emotionally resonant performance or work that serves as a fitting farewell or legacy of the individual's talent and dedication.