The last two chapters of Part 1 complete the background for the trial that is coming in Part 2. Scout and Jem learn some impressive things about their father — things that will ultimately help them understand why Atticus is compelled to defend Tom Robinson. The children also confront ugliness and hostility, only to find that the reason behind the behavior follows the ethical high ground.
The title of To Kill a Mockingbird is explained in Chapter 10. When Atticus procures air guns for Scout and Jem, he warns them to "'remember it's a sin to kill a mockingbird.'" This statement surprises Scout — Atticus doesn't make a habit of saying that things are sinful. Scout takes her confusion to Miss Maudie who explains, "'mockingbirds…don't do one thing but sing their hearts out for us.'" Boo Radley and Tom Robinson are both mockingbirds in this story, but Scout doesn't realize that fully until the end of the novel.
Beyond the mockingbird image, Lee continues bird symbolism in the case of the bird dog, Tim Johnson. Tim is "the pet of Maycomb," but one day the children discover him acting strangely. Calpurnia confirms that the dog is very sick, and consequently, very dangerous. Although the children recognize that the dog's behavior is odd, he doesn't look mad to them. Mad dogs are supposed to have certain characteristics, as Scout testifies when she says, "Had Tim Johnson behaved thus, I would have been less frightened." Significantly, Scout will learn that the town behaves much like Tim Johnson during Tom's trial. They appear to be the same, but danger lurks beneath. More significant still is that as Tim approaches the neighborhood, even the mockingbirds become still.
