“Caged Bird” has a sorrowful tone that reflects the speaker’s paradigm of constrained freedom. The poem’s sorrowful tone emerges in part from its constitutive tension between freedom and constraint. Angelou sustains this tension in various ways. Most obvious, though, is the way the poem alternates between the perspectives of two birds. Each of the poem’s two halves follows the same basic pattern, starting with one stanza on the free bird, followed by two stanzas on the caged bird. This alternating pattern introduces a comparison between the two birds. It’s important to note, however, that by moving from the free bird to the caged bird, the thematic trajectory of each half of the poem passes from aspiration to repression. This passage is marked by the preposition “but,” which opens stanzas 2 and 5. In both cases, “but” initiates a shift from the joys of the free bird to the sorrows of the caged bird. Angelou emphasizes this “downward” trajectory further by including two stanzas about the caged bird for every one about the free bird. The ultimate focus, then, is on the plight of the caged bird, made that much more tragic when compared to the free bird’s liberty.