Harper Lee's aptly-titled novel, To Kill a Mockingbird, emphasizes a running theme of innocence and beauty by utilizing the symbolic nature of the popular songbird.
When he gave us our air-rifles Atticus wouldn’t teach us to shoot. Uncle Jack instructed us in the rudiments thereof; he said Atticus wasn’t interested in guns. Atticus said to Jem one day, “I’d rather you shot at tin cans in the back yard, but I know you’ll go after birds. Shoot all the bluejays you want, if you can hit ‘em, but remember it’s a sin to kill a mockingbird.”
That’s the only time I ever heard Atticus say it was a sin to do something, and I asked Miss Maudie about it.
“Your father is right,” she said. “Mockingbirds don’t do one thing but make music for us to enjoy. They don’t eat up people’s gardens, don’t nest in corncribs, they don’t do one thing but sing their hearts out for us. That’s why it’s a sin to kill a mockingbird.”
It is this characteristic of the mockingbird--making beautiful music without any apparent faults--that Miss Lee stresses throughout the novel. Many of her sympathetic characters take on the role of human mockingbirds. Most of the children in the novel are mockingbirds, particularly Jem, Scout and Dill. They are small and innocent who create only joy and happiness to those around them (except for the occasional mischief they cause when they get together). Like the mockingbird, who witnesses much human hatred and suffering, the kids are also forced to see the negative side of life at an early age. Dill, in particular, has been subject to his parents' broken marriage and lack of attention.
The primary adult human during the first half of the book is Arthur Radley, known to most of Maycomb as "Boo." Although his early troubles as a teen does not qualify him as an innocent, he is reborn as Boo once he retreats behind the walls of the Radley Place. Like the mockingbird, he views the world from afar, and he is thrust into it through the actions of others whose curiosity in the Radley legend will not let him be. His innocence is conveyed through his attempts to befriend the young Finch children, and he shows his gentle nature when he mends Jem's pants and covers Scout with a blanket on the night of the fire.
Tom Robinson is also a mockingbird. Although he does not become a major focus of the novel until after Chapter 10, it is obvious that this poor, simple black man is up against a stacked deck in Maycomb's white world.
There are several other references to the mockingbird (Mr. Underwood's editorial, Scout's analogy on the night of Bob Ewell's death), but they occur in Part Two.