In "To Kill a Mockingbird," how does Jem act like a mockingbird?

The definition of a mockingbird in the novel is Atticus' description of a creature that doesn't do any harm and also gives pleasure. In that regard, Jem could be described as something of a mockingbird. But, unlike Boo Radley or Tom Robinson, the true mockingbirds of the story, it takes Jem time to mature into one. At first, Jem takes part in the Boo Radley game, unaware of the harm he may be doing to people in the Radley house who can hear the children make fun of Boo. He also chops down Mrs. Dubose's roses. However, when Nathan fills the tree hole with cement, Jem cries because he realizes how important that hole was to Boo. He also reads to Mrs. Dubose after he almost destroys her garden, and later finds he has helped her to overcome her morphine addiction. When Scout and Jem sleep on the patio, Scout wants to kill a roly-poly bug. Jem stops her, saying the bug never did anything to harm her. And Jem show bravery when a mob shows up at his house by telling his father he has a phone call. Most importantly, Jem protects his sister against an attack from Bob Ewell and may have been killed if Boo Radley had not intervened. So I would describe Jem as a young mockingbird about ready to leave the nest when the novel ends.