From line 2 the speaker of the poem is observing of nature and all its surroundings. He describe the beautiful landscape around the bird, but then he ends the stanza with mentioning the bird is encaged.
The speaker says I in the poem several of times, but doesn't exactly address who the speakers is. Also he seems to generate a unique unspoken bond with the caged bird in result giving the speaker a sense of understanding of the bird emotions and feeling. Although the speaker isn't stated in the poem. I think the speaker might be Dunbar himself, because Dunbar is a African American growing up in a time where Jim Crow laws, segregation, and inhumane treatment. Therefore, allowing the speaker to connect with the oppressed bird in the cage.
Dunbar starts the poem out stating he knows what the caged bird feels in the first stanza then fill the lines with descriptions of a open landscape on a sunny day. But he doesn't say what the caged bird actually feels. Then in the second stanza he says “I know why the caged bird beats its wing”, but throughout the stanza he just describe the bird's pain and suffering. Yet does not state why the bird beats his wing. Dunbar does the same in third stanza when he says “I know why the caged bird sings”, without say exactly what makes the bird