The major symbolism is this story is in its title. The story is about Brother and his relationship with his disabled brother, Doodle. However, the title of the story is the name of a bird. The point the author is trying to make is that Doodle and the Scarlet Ibis have much in common. Both have "flown" beyond expectations, the bird is hundreds of miles from its home and Doodle functions way above the expectations for him. Both have been injured on their life's journeys. The ibis is bloody and near death when Doodle notices him. Doodle's heart has been weakened by the strain Brother puts on him. Doodle is the only person to really care about the bird and buries him carefully. He and the bird both die on the same day, indicating a connection that lies deeper than just compassion. Thus, the scarlet ibis is a symbol for Doodle and his struggle to fly beyond expectations.
Yes, of course the scarlet ibis refers to Doodle. This is because of the rareness in both creatures. Also at the ending of the story the apperiance of Doodle his neck, legs arms and clothing that was died red with blood all resembeled the scarlet ibis. Another symbol is the mahogany coffin symbolized Doodle's death and how everyone thought that he was going to die and when his brother, the narrator, made him touch it.