The premise of Du Maurier's story is a fairly destructive one. The birds win. Humanity suffers. Yet, in Nat's characterization, one can see how Du Maurier defines the contours of survival. Du Maurier taps into the human ability to survive, something that Faulkner might call the "cursed capacity for suffering."
This "cursed capacity" is seen at different points in the story. For example, at the story's end, Nat's characterization captures what Du Maurier sees as a necessary condition for survival. Rather than respond to his wife who pleads for America "to do something," Nat focuses on defending his family and himself against the coming onslaught:
Nat did not answer. The boards were strong against the windows and on the chimneys too. The cottage was filled with stores, with fuel, with all they needed for the next few days. When he had finished dinner he would put the stuff away, stack it neatly, get everything shipshape, handy like. His wife could help him, and the children too. They’d tire themselves out, between now and a quarter to nine, when the tide would ebb; then he’d tuck them down on their mattresses, see that they slept good and sound until three in the morning.
Nat does not answer his wife who looks for help from abroad. He simply focuses on survival. Du Maurier focuses on the intensity with which Nat puts the boards on the windows and chimneys. Nat's resolve towards survival is met with the resilience of his family. They help him, even to the point where "they'd tire themselves out." This quote shows the role of survival in the story.
Continuing from this point, Nat defines consciousness as continually redefining ways to defeat the birds even when the odds for survival do not look good. The birds swarm with greater intensity and greater focus, and yet Nat is driven to survive:
He had a new scheme for the windows, which was to fix barbed wire in front of the boards. He had brought a great roll of it from the farm. The nuisance was, he’d have to work at this in the dark, when the lull came between nine and three. Pity he had not thought of it before. Still, as long as the wife slept, and the kids, that was the main thing.
Nat's survival is shown in his desire to protect his family, "the main thing," and not succumb to the overwhelming forces of the birds. Nat's survival is embedded within him, constantly thinking about ways to find victory. While Nat would have every reason to concede that the birds have greater paths to victory, he does not let such thinking enter his mind. Instead, survival is defined as caring for his family and seeking a way to find success.
In Nat's characterization, Du Maurier constructs survival as possessing the will to take action. Nat confronts some very unsettling aspects of reality. Yet, he does not allow negative thoughts to permeate his drive to survive:
“There isn’t going to be any news,” said Nat. “We’ve got to depend upon ourselves.”
He went to the door and slowly pulled away the barricades. He drew the bolts and, kicking the bodies from the step outside the door, breathed the cold air. He had six working hours before him, and he knew he must reserve his strength for the right things, not waste it in any way. Food and light and fuel; these were the necessary things. If he could get them in sufficiency, they could endure another night.
In this moment, du Maurier defines survival as a fierce self- sufficiency that is motivated by the will to act. Nat tells his wife that outside intervention is secondary and that there has to be self- reliance in order to survive. At the same time, Nat understands that survival is dependent on harnessing "the necessary things" and maximizing their usefulness. This becomes a critical part of survival in challenging situations. Du Maurier constructs survival as a reality in which individuals possess mental toughness, and harness their skills and knowledge towards living.