The birds themselves are layered symbols that highlight multiple themes. In Nat’s mind, the birds clearly symbolize the German bombers from World War II, which gives him an advantage. Nat sees how the birds organize themselves into clearly defined ranks with specific targets, just like the Luftwaffe; his wartime memories help him predict the birds’ tactics, and he knows how to prepare for an air-raid (only his cottage will be hit by hordes of birds rather than bombs). This symbolism connects the birds to the theme of memory—and memory is what saves Nat and his family.

The fact that the birds can symbolize trained bomber pilots exposes how unnatural their actions are. Birds imitating humans for destructive purposes is exactly the kind of bizarre aberration that supports the theme of The Uncanny Natural World. In this way, the birds—especially the “suicide” birds, “the death-and-glory boys” (93)—symbolize Nature as an angry entity that is willing to break its own rules and destroy itself in its war with humans.

The birds also symbolize elements of the Cold War. The birds become violent when the east wind blows, which parallels the KGB’s influence over the British citizens they recruit.