The Happy Prince had compassion for the poor. How do you think the swallow came to know about the prince?

The story tells us how the swallow comes to meet the statue of the Happy Prince. The swallow had been courting a reed who had attracted him earlier in the spring with her graceful, slender waist. However, when she tells him she is too attached to her home to go away with him, he decides to leave her and fly to Egypt to find the other swallows.
Before he leaves, however, he decides to sleep one night in a nearby city. He settles down on the statue of the Happy Prince, pleased that he has a "golden bedroom" with lots of fresh air. He plans to sleep on the statue's feet.
It's only when he is hit with the statue's teardrops that he meets the statue. The statue then tells the swallow the story of his life, saying:

"When I was alive and had a human heart," answered the statue, "I did not know what tears were, for I lived in the Palace of Sans-Souci where sorrow is not allowed to enter. In the daytime I played with my companions in the garden, and in the evening I led the dance in the Great Hall. Round the garden ran a very lofty wall, but I never cared to ask what lay beyond it, everything about me was so beautiful. My courtiers called me the Happy Prince, and happy indeed I was, if pleasure be happiness. So I lived, and so I died. And now that I am dead they have set me up here so high that I can see all the ugliness and all the misery of my city, and though my heart is made of lead yet I cannot choose but weep."

The swallow is as compassionate as the Prince, so rather than fly away, he stays put, and the two work together to help the poor of the city.