No.  the saying that a swan sings only when it is about to die is a myth.  This old idea came from the ancient Greeks, who believed that these graceful water birds were creatures of Apollo, the god of music.

Fabled as being voiceless during its lifetime, the swan was thought to possess the special powers to sing a song of great sweetness at the moment of its death, as a tribute to Apollo.

The myth has been memorialized by poets and composers for centuries.  Even today, an artist’s farewell performance or last piece of work is often called his “swan song.”– Dick Rogers