The Symbol of the Mockingbird Lies at the Heart of Harper Lee's Novel to Kill a Mockingbird. Discuss.

Mockingbird's are not only symbols of innocence; they are also symbols of happiness and to kill them is evil. This concept, the senseless persecution of an innocent individual, is central to Harper Lee's novel. Boo Radley and Tom Robinson are both mockingbird figures, innocent yet condemned through the prejudices of society.
The symbol of the mockingbird, with its associated ideas of a fragile, albeit beautiful innocence appears when Atticus tells Jem and Scout they may shoot all the bluejays they want, "but remember it's a sin to kill a mockingbird". This is the first time Scout has ever heard Atticus say it was a sin to do something. The full significance of this remark is explained to Scout by Miss Maudie as she explains that mockingbirds "do nothing but sing their hearts out for us", making music for the enjoyment of everyone in Maycomb. They represent a type of gentle and harmless creature. Throughout the text, Lee reiterates that to kill a mockingbird would be wicked and spiteful, a senseless and pointless act of destruction.
Boo Radley symbolises a beautiful, but tortured mockingbird that is misunderstood and ostracised by both his family and the wider community. He is kept as a prisoner in his own home, kept in confinement by his god-fearing Baptist family. Despite this treatment Boo remains gentle and harmless. However, people tell stories about how he eats squirrels and cats and poisons the pecan nuts in the school yard. To the community Boo is a "malevolent phantom". Gradually Scout and Jem begin to see things from Boo's perspective. Like the mockingbird Boo gives pleasure and comfort: for example, the gifts in the tree, the blanket placed around their shoulders as they watch Miss Maudie's home go up in flames. Finally, he saves Scout and Jem's lives. In turn, Scout realises to drag Boo into the limelight would be like "shootin' a mockingbird" and a cruel betrayal of all the inherent goodness Boo symbolises as a mockingbird.
The mockingbird symbol also involves the broader themes of justice and how it can destroy an innocent person. Tom Robinson is an honest and principled black man who is accused of raping a white girl, Mayella Ewell. He explains he was only in the Ewell's house to help her; however, he condemns himself in the eyes of the jury when he says he felt sorry for her. This would be seen as the lowest class of citizen showing superiority towards a class above. The white community's fear of racial disturbance and their insecurity about their own position in society meant that Tom Robinson was found guilty. The prosecutor responds with feigned indignity "You felt sorry for her; you felt sorry for her?" Harper Lee uses rapid dialogue in the courtroom scene to emphasise the way the prosecutor attacks Tom, like an attack on an innocent mockingbird. Harper Lee exposes not just the prejudices of Maycomb but the ugly nature of such beliefs in society as a whole. Justice is betrayed when the jury ignore the evidence and destroy the mockingbird figure of Tom Robinson.
It is evident that both characters have mockingbird traits. They both show kindness - Boo to the children, Tom to Mayella. They are both innocent - Boo of the evil persona with which he is associated and Tom of the crime of rape. Both are victims of prejudice. The significance of the mockingbird motif broadens out to contain many layers of meaning and is kept alive through the narrative continually reminding the reader of the theme of prejudice with which it is associated.