It is time for the reader to overcome his/her challenges and move on.

Learning to fly is symbolic for moving on because when you learn to fly you now have the the ability to move around more like you can do after you move on.

Singing in the dead of night represents how you want to move forward but you cant so you are hiding a want from society, like a bird is hiding by not singing during the day.

Into the light of the dark black night represents taking on you challenges. The dark represents you challenges and the light represents you trying to overcome your challenges and bring goodness(light) into a situation.