Whistlestar by Cat Stevens is an instrumental track that evokes a sense of nostalgia and tranquility through its melodies. As there are no lyrics, the song's meaning is open to interpretation, often reflecting the listener's emotions and thoughts. The key themes revolve around serenity, introspection, and the beauty of simplicity. The poignant moments are conveyed through the changes in melody and rhythm, which can take the listener on an emotional journey.