“The caged bird…. sings of freedom”

Again the poet compares the free bird to a caged bird who can only sing fearfully. Due to the lack of freedom, most of the things from the outer world are unknown to the caged bird so he longs for them.

A song travels from place to place so the song of the caged bird can also be heard in distant hills. It means, her claims for freedom through her poetry are now known in distant places too.