bird out and throws it on the road, but he immediately feels regretful. This makes Siddhartha realize that he is oppressed in his current life station and needs to escape somehow.  Siddhartha realizes that obtaining money and material wealth doesn't lead to happiness.  Siddhartha realizes that he is not able to truly love another person, so he can't find happiness that way, either.  This leads Siddhartha to wish for escape from his current life in order to find his innocence again. 

For much longer, he could have stayed with Kamaswami, made money, wasted money, filled his stomach, and let his soul die of thirst; for much longer he could have lived in this soft, well upholstered hell, if this had not happened: the moment of complete hopelessness and despair, that most extreme moment, when he hang over the rushing waters and was ready to destroy himself. That he had felt this despair, this deep disgust, and that he had not succumbed to it, that the bird, the joyful source and voice in him was still alive after all, this was why he felt joy, this was why he laughed, this was why his face was smiling brightly under his hair which had turned gray.

In conclusion, let's talk about Kamala.  In regards to Kamala, even though the songbird still symbolizes a trapped Siddhartha, she takes a different approach to freedom.  Where Siddhartha wishes for the bird's death for it to obtain freedom. Kamala realizes that she can be part of the process by setting the bird free.  Kamala sets Siddhartha free as well.  He needs to follow a different path and will not return. 

Kamala keeps her bird in a golden cage. It may be golden, valuable, and beautiful, but it is still a cage. Similarly, during Siddhartha's time in the essential world, the city, he may be surrounded by things that seem very valuable and important, but they are, ultimately, a cage for him, too. His pleasure garden does not truly bring him anything worthwhile or important. He must escape his "golden cage" in order to reach enlightenment because it will not be possible when he is weighed down by the material world.  

In a dream, Siddhartha hears that Kamala's bird has gone silent. He looks inside the cage and notices that the bird is, in fact, dead. He takes it out of its cage and weighs it in his hand for a moment. Then, he throws it away into the street, and "in the same moment, he felt terribly shocked, and his heart hurt, as if he had thrown away from himself all value and everything good by throwing out this dead bird."

The golden cage may seem to be the thing of value, but it is really the life inside, symbolized by the bird, that is important and valuable.

The songbird represents Siddhartha’s inner voice, which he vowed to listen to as he explored the sensual side of himself.  In the beginning of the fifth chapter (“Kamala”) Siddhartha told himself, “He wanted to strive for nothing but what the voice commanded him to strive for” (19).

Slowly through his time spent learning the sensual and physical side of himself with Kamala and Kamaswami, Siddhartha’s inner voice gradually becomes quiet. He indulges his senses through food and drink, gambling and Kamala. “Siddhartha's new life after he separated from Govinda had become old, losing color and splendor as the years went by, or gathering wrinkles and stains, and showing ugliness here or there. Hidden at the bottom, disappointment and disgust were waiting; Siddhartha did not notice it” (31). Siddhartha only noticed that his life had become stale and miserable. He had reached such a point of self-loathing that he had giving himself to the idea of suicide. Siddhartha felt that the bird, which was a symbol of his inner voice, had died. “Dead was the bird in his heart” (34).

He went to the river to throw himself in and end his life when he heard the holy word, “om,” which reminded him of the indestructibility of life and wheel of reincarnation. He has a wonderful epiphany and realizes that his inner voice has not died. “He laughed because the bird, that joyful source and the voice within him was still alive after all” (38).

So in that sense, the songbird (and Siddhartha’s dream that it had died) symbolized the effects of the “essential” (physical/sensual) world on Siddhartha’s inner voice.