He uses a short apocryphal story of baby Jesus being given a clay goldfinch for a toy and bringing it to life as a metaphor to indicate that Bird brings jazz music to life. The majority of paragraph three is Ellison going through the species of the goldfinch and how it is characterized, then at the end he hits the reader with the problem of why it does not relate to Bird; its like the canary. Paragraph four goes on to show the similarities the mockingbird has that connect it to Bird himself.
The sentence structure in paragraph four mimics that of a saxophone holding a long, drawn out note. The sentences are long and drawn out, making the reader have to take a breath in between because the sentences are so long which would happen if a jazzman were playing the saxophone. He is connecting the sound of a saxophone to the sentence structure of the paragraph. The last paragraph also sums up the idea that Bird had a complex life but it didnt minimize his greatness. All of these strategies bring the reader back to the purpose of the essay which proves that Charles Parker was a most inventive melodist-a true songster.