High above us in the darkness a solitary mocker poured out his repertoire in blissful unawareness of whose tree he sat in, plunging from the shrill kee, kee of the sunflower bird to the irascible qua-ack of a bluejay, to the sad lament of Poor Will, Poor Will, Poor Will.
– Harper Lee
To Kill a Mockingbird, Chapter 28. The mocker is a mockingbird, standing for innocence and defenseless beings. The bluejay represents malevolent creatures that harm others. Boo Radley is a symbolic mockingbird and Bob Ewell a bluejay. The closeness of both birds in the same tree foreshadows Ewell’s attack on the children and Boo defending them.