Describe Ralston's reaction to a black bear in his campground on his first solo overnighter?

When Ralston first camps overnight on a solo trip, he encounters a black bear that wants his food bag. Instead of letting the big black bear have his food bag, he decides to challenge the bear with a large stick. The bear actually backs down and walks away. However, the next day, the black bear comes back and stalks Ralston on his hike. Ralston yells and throws rocks at the bear until it retreats.