You could read Chapter Nineteen for the answer
Answer:
It means that nobody lives long enough to make every mistake so when someone makes a mistake learn from it so you wont make the same one.
Explanation:
Its kinda self explanatory
I believe that the thrush's song changed the mood because it was a song filled with hope from the divine that inspired him. Darkling Thrush refers to a bird who is weak and fragile, however, even with these qualities, he sacrificed himself.
