In “The Birds,” Nat Hocken has the apparently impossible struggle of keeping himself and his family safe from the vicious attacks of killer birds. Nat's efforts to survive form the heart of the story, allowing the author to explore the human response to extreme danger, and Nat is motivated primarily by a desire to protect himself and his family.
Nat is especially attuned to the natural world, so he is immediately aware of the birds' changing habits. They are becoming aggressive and nasty, yet Nat seeks some kind of natural explanation. This is a normal human response; Nat wants to understand the world around him.
Yet this world has quickly become extremely unfamiliar, and Nat must focus on keeping himself and his family alive. He blocks and fights the birds in every way he can think of, and survival becomes a priority in a way it has never been before. Du Maurier spends so much time on these efforts to survive in order to explore the lengths human beings will go to keep on living and their emotional responses to such stress.
Nat actually does very well at keeping his fear under control. Guided by his reason and knowledge, Nat works logically to secure his house the best he can. He also strives to calm his wife and children in their fear. He thinks of small tasks for them to do and cheers them up as best he can, always putting their needs and safety before his own. Nat would sacrifice his life for his family if necessary, and in the end, he brings them close to him to await the final attack, consoled that at least they will die together.
Finally, Du Maurier uses this story to reflect on how little control human beings actually have over the natural world. We humans like to think that we are in charge and that we can change our circumstances and our environments according to our own will. Very often, however, this is not the case, and Nat Hocken's story allows us to see that clearly.