How we cite our quotes: (Line)
Quote #1
When the sun is bright on the upland slopes;
When the wind stirs soft through the springing grass,
And the river flows like a stream of glass; (2-4)
By giving us a description of this beautiful natural landscape, the speaker gives us a sense of just how much the caged bird is missing out on. Who'd want to be in a cage when they could be flitting around slopes and grass and dipping into a "stream of glass"?
Quote #2
When the first bird sings and the first bud opes,
And a faint perfume from its chalice steals—
I know what the caged bird feels! (5-7)
We get more lovely description of nature here. The caged bird not only misses out on the beautiful "perfume" of the flower bud, it also misses out on hanging out with its other bird buddies. So even though these lines are describing beautiful things, they evoke a sense of loss. And the speaker identifies with the bird's sense of loss.
Quote #3
For he must fly back to his perch and cling
When he fain would be on the bough a-swing (10-11)
Again, in these lines the speaker lets us know that there's nothing the bird would rather be doing than being out in nature, chillin' on a tree branch (or "a bough"). Nature represents freedom, but the bird is denied access to nature and freedom. He's stuck in his little perch in the cage.