What is the theme in Brian's Winter by Gary Paulsen?

Survival is a theme in the story. Brian has already survived fifty-four days alone in the woods after a plane crash when this novel begins. In a prior novel, Brian is rescued at this point, but the author rewrites his story in order to satisfy his reader's curiosity. In this novel, Brian must survive winter before he can be rescued. Brian finds a gun, two lighters, fishing gear, and other survival items in the plane on which he crashed. Brian uses the gun exclusively for a time, but when the firing pin breaks, Brian finds himself once more reliant on a bow and arrow. Brian survives by eating rabbits and foolbirds, but eventually realizes that winter is coming on and he must think bigger.