It was in the clove of seasons, summer was dead but autumn had not yet been born, that the ibis lit in the bleeding tree.
One sentence that could be interpreted as echoing this opening sentence is this one:
How many miles it had traveled to die like this, in our yard, beneath the bleeding tree.
For, this sentence, like the first one is a metaphor for what happens with Doodle. When describing Doodle as helpless and crying for the first time, "Don't leave me. Don't leave me," it is summer. Then, Doodle's final summer, the summer of 1918, there is a blight and the crops wither and die. During that summer, too, names from French killing fields of World War I are also mentioned. After the scarlet ibis lands and dies in their tree and Doodle buries it, the boys hurry to Horsehead Landing, what will be Doodle's killing field.
It is the same season as that in which the ibis lands in the tree: "The sun, gilded with the yellow cast of autumn still burned fiercely." But the fire of the sun is soon quelled by a storm. And, after Brother leaves Doodle in the rain and can no longer hear his voice, he feels he must return for Doodle, sensing that something has happened.
Finally I went back and found him huddled beneath a red nightshade bush beside the road.
How many "miles" Doodle has come from a paralyzed baby to a boy who can walk, and swim, and row a boat only to die in the storm, so much like the scarlet ibis that has come from a nest to become an adult bird who travels so far only to die from the storm. So much like the bird, Doodle's neck is "vermilion" from his having bled from the mouth; his little legs, bent at the knees, "had never before seemed so fragile, so thin."