In the poem, "Sympathy,"how is the use of nature used to highlight freedom as contrasted to being shut in a cage?Paul Laurence Dunbar's "Sympathy"

The songbird that sings is much like the singing cotton
pickers that harbored inordinate rage at their condition.  For, both sing to keep
themselves from total despair.  In fact, "Sympathy" is a lyrical poem suggestive of a
blues song in its melancholy.

The speaker of Dunbar's
poem says that he "knows what the caged bird feels" as he sees the sun brightly shining,
the wind stirring, and the river flowing.  When the unfettered freedom of nature
presents itself in contrast to his own condition, the speaker feels frustration at his
own personal lack of freedom.  Like the bird, he cannot be free, hindered by the bars of
conventions of society.  Instead, he "must fly back to his perch" and remain in his
limited and oppressed environment.

And, yet, like the caged
bird, the speaker must strive to attain freedom, he, too, must send a plea Heavenward
that someday he will be recognized as an individual who deserves respect and
opportunity.  He must persevere, or else he will surely die.