The central motif of birds gives the author the opportunity to explore a range of themes. The miracle of bird migration becomes symbolic, echoing Jim's journey across the globe to the war. The notion of the 'bird's eye view' is explored.
The author uses birds as a recurring theme to examine different ideas and concepts. The wonder of bird migration serves as a metaphor for Jim's global travels during wartime, while the idea of seeing the world from a bird's-eye perspective is also explored.