Hurst gives us a clue that the ibis is very important in the story by naming the story "The Scarlet Ibis." The title refers to the tropical bird that was blown off course and landed in the narrator's yard, but it also refers to Doodle. The scarlet ibis is a symbol for Doodle himself. The ibis is a beautiful bird who ends up in the wrong place. It does not belong at Doodle's house and it cannot survive there. It has been through a terrible storm and dies from exhaustion. No one in Doodle's family appreciates its beauty or rare presence.
This description applies to Doodle, as well. Doodle is a beautiful boy, despite his physical disabilities. His heart is full of love. There is no meanness in him, only gentleness. (It is Doodle who struggles to bury the ibis while his family laughs at him from the window.) Doodle's family is the wrong place for him to grow and thrive. They do not value him for the wonderful gift he is to them. He cannot and does not survive in that environment. At the conclusion of the story, Doodle, too, goes through a terrible storm and dies from exhaustion.
Hurst makes this symbolism clear in the story's conclusion. In death, Doodle looks like the scarlet ibis when it died. The narrator refers to Doodle as "my fallen scarlet ibis."
It symbolizes Doodle when the big brother runs to him seeing him with the blood all over Doodle's body as the scarlet feathers did to the dead ibis.