Swan song is a metaphorical phrase for a last gesture, effort, or performance just before death or retirement. It refers to an ancient belief that swans sing a most beautiful song just before they die, having been silent for most of their lives. This belief, the basis of which has long been debated, was proverbial in ancient Greece by the 3rd century BC and was repeated in later Western poetry and art. Swans learn various calls throughout their lives. Their calls are most distinct during mating rituals and are not associated with death...