Course Hero. "To Kill a Mockingbird Study Guide." Course Hero. 2 Sep. 2016. Web. 14 Nov. 2018. <https://www.coursehero.com/lit/To-Kill-a-Mockingbird/>.
Course Hero. (2016, September 2). To Kill a Mockingbird Study Guide. In Course Hero. Retrieved November 14, 2018, from https://www.coursehero.com/lit/To-Kill-a-Mockingbird/
(Course Hero, 2016)
Course Hero. "To Kill a Mockingbird Study Guide." September 2, 2016. Accessed November 14, 2018. https://www.coursehero.com/lit/To-Kill-a-Mockingbird/.
Course Hero, "To Kill a Mockingbird Study Guide," September 2, 2016, accessed November 14, 2018, https://www.coursehero.com/lit/To-Kill-a-Mockingbird/.
Professor Bradley Greenburg from Northeastern Illinois University explains symbols in Harper Lee's novel To Kill a Mockingbird.
The mockingbird is a symbol of innocence or vulnerability. Several characters lose their innocence in the novel—most notably Tom Robinson. When he is killed the newspaper editorial compares his death to the "senseless slaughter of songbirds," a direct reference to Atticus's earlier warning to his children that it's a sin to shoot a mockingbird because a mockingbird does nothing but bring joy to people. Similarly the sheriff refuses to arrest Boo Radley because doing so would be "sort of like shootin' a mockingbird," meaning that Boo is such a vulnerable character that it doesn't make sense to bring him extra hardship. In the same vein Scout's last name Finch, another songbird, suggests that her innocence (or loss of) will be integral to the story's plot.
Many characters in the novel face a physical (or mental) challenge: Tom Robinson has a mangled left arm; Jem breaks an arm badly enough that his arm, too, is forever altered; Boo Radley has a damaged spirit; Atticus has poor eyesight. These disabilities—or differences—are outward signs that everyone has weaknesses and carries with them the damages inflicted by life.
Boo has been living as a recluse for many years but obviously wants to connect with the outside world. Boo leaves gifts for Jem and Scout in the knothole of the tree as a way of connecting with them without making himself vulnerable. When Nathan Radley learns what Boo had been doing, he fills the knothole with cement, breaking Boo's ties with the outside world in an attempt to keep him secluded.
Tim Johnson, a dog well known in Maycomb, becomes rabid—and a danger to the community. The dog's disease is symbolic of racism in the town. Just as Sheriff Tate refuses to serve justice in the Tom Robinson case, so does he refuse to shoot the rabid dog—he urges Atticus to fight it, just as Atticus fights for justice in the courtroom. Miss Maudie aptly tells Scout she believes that Atticus "decided he wouldn't shoot till he had to, and he had to today."