Why Harper Lee used mockingbird?

Harper Lee used the metaphor of the mockingbird in her novel "To Kill a Mockingbird" to symbolize innocence, beauty, and vulnerability. Just as mockingbirds are harmless creatures that bring joy through their song, Lee suggests that certain individuals in society, such as Tom Robinson and Boo Radley, are also innocent and should be protected from harm. By using the mockingbird as a symbol, Lee highlights the theme of empathy and understanding towards those who are unfairly judged and mistreated.