That lets the trees and water enter
Until the Sunday sombre bell at dark
Eating bread from a newspaper
Drinking water from the chained cup
That the children filled with gravel
In the fountain basin where I sailed my ship
Slept at night in a dog kennel
But nobody chained him up.
Like the park birds he came early
Like the water he sat down
And Mister they called Hey Mister
The truant boys from the town
Running when he had heard them clearly
On out of sound
Past lake and rockery
Laughing when he shook his paper
The truants are cowardly, taunting him but running away when the hunchback hears and responds to them. 
 Alternatively, it is the hunchback who runs when he hears them, running till he can no longer hear them. 
 The syntax doesn’t make it clear whether the subject is the singular hunchback or the plural boys.
The Hunchback in the Park