Birds final words are from Book IV of Miltons "Paradise Lost".  When Lucifer is found in Paradise by two Cherubs, he rebukes them  for not recognizing him. They rebuke right back saying that his  appearance has changed from being in Hell. "So spake the Cherub; and  his grave rebuke, Severe in youthful beauty, added grace Invincible:  Abashed the Devil stood, And felt how awful goodness is, and saw  Virtue in her shape how lovely; saw, and pined His loss"