To Kill A Mockingbird Help?

The quote "I'd rather you shot at tin cans in the back yard, but I know you'll go after birds. Shoot all the bluejays you want, if you can hit'em, but remember it's a sin to kill a mocking bird." Atticus said this to Jim after Atticus had bought the kids air-rifles but would not teach them how to shoot. Atticus was accepting that they would shoot birds, but did not want to be responsible for teaching them. Likewise, he accepts the fact the Tom will be convicted, but still defends him. Scout ask Miss Maudie about this and she says that "Mockingbirds don't do one thing but make music for us to enjoy...That's why it's a sin to kill a mockingbird." This is in chapter 9.