To kill a mockingbird

What does the "mockingbird" symbolize in the story

In this story of innocents destroyed by evil, the 'mockingbird' comes to represent the idea of innocence. Thus, to kill a mockingbird is to destroy innocence." ... Later in the book, Scout explains to Atticus that hurting their reclusive neighbor Boo Radley would be "sort of like shootin' a mockingbird."

It represents peacefulness, innocence and kindness which is portrayed through the characters of Boo Radley and Tom Robinson.