The island children are warned away from the Birdman through superstition and fear. When Gracie defies this, she discovers someone entirely different from the frightening figure described to her.
The novel is an early ecological story: the islanders who killed the narwhal were destroyed; those who help it live. Morpurgo argues for living in harmony with nature rather than exploiting it.
The curse of Samson is bound up with the island's history and collective memory. The Birdman is the last keeper of that history.