What are the symbols of death in The Scarlet Ibis?

the red bird. the bird and boy have similarities before the bird dies. and some things of how the bird dies somewhat happens to the boy.

In addition, the story opens with the brother recounting how this happened years ago when a "bleeding tree" stood near the front door. Now it is gone. Brother mentions that Doodle's name William Armstrong is more fit for a tombstone than for Doodle. Doodle's father made a coffin for Doodle because he was not expected to live. Doodle touches it at one point. A local boy has died in one of the battles of World War I.