The obvious answer to this question is Boo Radley. At the end of the novel, we see that Scout learns the lesson of not killing the mockingbird. As she was told in the begining of the novel, a mockingbird only sings all day and makes people happy, so one should never kill the innocent bird. Boo Radley had reached out the the children and tried to become their friend. Unknown to them, he was watching out for them and he protected them, so why tell the law what really happened on that dark night? It would be an instance of when doing the legal thing was not really the right thing. Sometimes we have to obey a higher power.
Who is the other mockingbird? Several possibilities, perhaps, but I think Tom Robinson is another mockingbird. He was a kind family man only trying to help Mayella. He said in court he felt sorry for her. He was an innocent man that was taken advantage of by a white-trash woman, and then made a scapegoat. What happened to Tom is in stark contrast of what happened to Boo. In Tom's case, justice was served, but it was injustice. Atticus did not want to make the same mistake with Boo Radley.
Most of the children in the novel could also be seen as mockingbirds. Jem, Scout and Dill would all qualify as innocents who, as children, should only bring happiness to those around them. All three face their own forms of mistreatment, however. Dill, particularly, has faced more unwanted turmoil during his life than should be expected. His parents send him to Maycomb each summer to be rid of him while they enjoy their own pursuits. Jem and Scout are nearly killed by Bob Ewell before another mockingbird, Boo Radley, steps in to help.
In this book, the mockingbird is seen as something that does not hurt anyone. Therefore, it is a sin to kill a mockingbird -- you are harming something that does no one any harm. The two people who are most like the mockingbird in this book are Tom Robinson and Boo Radley.
Both Tom and Boo are persecuted by various people in the town even though they have not hurt anyone. Boo is treated as a monster and Tom is falsely accused of rape. They both are, it would appear, good people. But various people in the town abuse them even so -- just because the people are more powerful and are able to abuse the two. This is why the two of them are the most obvious "mockingbirds" in the story.
the roly poly scout almost kills
..they are both characters who are innocent and are punished/ killed for no reason..they are not harmful or hurtful but they are punished anyway, just like the mockingbird.
all the mockingbird does is sing and bring joy to people. they are not harmful to anyone in anyway, but jem and scout were almost going to shoot themmm