I’m maya angelou’s poem “caged bird”, why does the cage represent ?

Maya Angelou’s poem “Caged Bird” symbolizes the caged birds African Americans who are caged in their own land by the whites. The cage in the poem represents the restriction of the society i.e., the natives are captivated and restricted on their own land. The captured bird has "clipped wings, tied feet, and bars of rage". They sing the song of liberty and are compared with the free birds.