How does the author use symbolism to enhance the narrative in "The Scarlet Ibis"?

The Scarlet Ibis is a story about faith and pride. It is a symbolic story in the sense that the events and places in it have a double nature: the cotton fields, the swamp, and Horsehead Landing are all real places, but they also come to have a second, spiritual meaning that Doodle and his brother share. The main symbol of the story, the ibis, can be understood as symbolic of Doodle himself. In this way we can understand Doodle as exotic (like the bird), perhaps out of place, or only a temporary visitor; like the bird, he is fragile and easily exhausted; the bird's death foreshadows Doodle's death.

But Doodle himself is a symbol of a sort; born with his head in a membrane ("caul") that Aunt Nicey says is made from "Jesus' nightgown," Doodle is from the start a baby not expected to live, perhaps not "all there," and a miracle child. The story of how Brother teaches Doodle to walk can be understood as symbolic of faith (Brother's faith in Doodle) made real. Seen in this way, Old Woman's Swamp is a magic, secret place where miracles occur; it is significant (and telling) that, in order to prove that Doodle really can walk, the scene has to shift to the decidedly unmagical dining room of the parents. Brother, who has a foot in both worlds, want to make Doodle fully "real" and permanent by making him stronger. This desire of Brother to forsake the special bond he has with Doodle is, as the narrator says, the work of pride, a "wonderful, terrible thing, a seed that bears two vines, life and death." Doodle's repeated calls for Brother not to leave him mean, first, not to leave him behind of course, but they also mean that Doodle knows that he will never become the "real brother" Brother craves. Brother, who knows what Doodle is, still chooses to try to make him into something else.

The appearance of the bird at the end of the story brings to a climax the symbolic nature of Brother and Doodle's relationship. The bird's presence is just as impossible as Doodle's survival, and like the bird, Doodle too is not long for this world. His desire to bury the bird shows that Doodle feels a kind of kinship to the creature. His own death, brought upon by Brother's decision to show no "mercy" and leave him behind during the storm, suggests that whatever the requirements might be for becoming a "real brother," Doodle was made for something else.

How do images in "The Scarlet Ibis" signify the literal and symbolic importance to plot development?

The bleeding tree is a striking image because it bleeds sap and this symbolically foreshadows Doodle's death. The scarlet ibis brings even more symbolic clarity to this first comparison. The ibis is actually (literally) red and in this story, this is certainly symbolic of blood. The bleeding tree and the blood red color of the ibis all symbolize Doodle's blood at the end of the story. Despite Doodle's progress (at the hands of Brother's selfish motivation), these morbid images keep emerging.

Doodle's coffin is also an image that literally and symbolically refers to death. Doodle's father had it made when he was born, thinking he would not survive. Doodle survives, but they keep the coffin. Brother cruelly torments him the coffin, making sure he knows it was made for him.

Even after Doodle survives his infancy and learns to walk, the family keeps the coffin. "Within a few months Doodle had learned to walk well and his go-cart was put up in the barn loft (it's still there) beside his little mahogany coffin." That image of death is literally and symbolically still there. Between the bleeding tree, the scarlet ibis, and the coffin, the story constantly uses images to foreshadow blood and death.