Another important point is what mockingbirds do for us (people). Maudie points out what they "don't do" like nest in corn cribs or mess up people's gardens. However, they make music and sing for us. This is how it truly ties in with both mockingbird symbols in this book. Tom Robinson goes out of his way to help Mayella when she needs it most. He expects nothing out of it at all. Then she blames him for something he didn't do, just to cover up what her alcoholic father does to her on a daily basis. Tom is the mockingbird just because he only helps when he can. He never harmed a hair on that girl's head. Boo is then the second mockingbird for risking his anti-social personality (and risking the opportunity to become a hero in the eyes of the town) to save the lives of "his children."
Atticus told Scout that it was a sin to kill a mockingbird. This was the first time that Scout had ever heard Atticus say that it was a sin to do something, so she asked Miss Maudie about it. Miss Maudie said that Atticus was right. She said that mockingbirds “don’t do one thing but make music for us to enjoy…but sing their hearts out for us.” The mockingbird was a metaphor for good and innocent people who are destroyed by evil. Boo Radley would be an example of one of the good and innocent people. He was kind to Jem and Scout even though he was damaged by an abusive father. In chapter 30, Scout tells Atticus that hurting Boo Radley would be “sort of like shootin’ a mockingbird.”
its a sin because unlike other birds mockingbirds just make beautiful music for humans and dont do anything to disturb anyone