In the novel To Kill a Mockingbird, Harper Lee tells us that mockingbirds are rather humble little birds, similar in size to finches. True to their name, they often copy the songs of other birds and are very sweet and harmless creatures. This is why Atticus Finch tells the children that it's a sin to kill a mockingbird. The Finch's neighbor Miss Maudie explains that 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."

The mockingbird can be compared, of course, to Tom Robinson, the African American man who was simply minding his own business and was falsely accused and convicted of a crime he did not commit. When Mr. Robinson tries to escape from prison, he is killed. The newspaper editor, Mr. Underwood, writes an article in the paper after this tragedy, comparing Tom's death to the senseless murder of innocent songbirds by hunters. Boo Radley is another blameless person who could get into big trouble for his actions, even though he did what he did to protect the children. It is interesting that the last name of the family is Finch, as Atticus is called upon to be a protector of the innocent in more than one instance.