For such a short poem, “Caged Bird” has a rather complex structure, one that’s defined by the poem’s constitutive tension between freedom and confinement. One way Angelou draws out this tension is through a repeating stanza pattern than alternates between the free bird and the caged bird. Whereas the first stanza focuses on the free bird, the second and third stanzas focus on the caged bird. This same pattern repeats in the second half of the poem: stanza 4 focuses on the free bird, and stanzas 5–6 focus on the caged bird. This pattern promotes a comparison between the two birds and their opposing situations. Each three-stanza section begins with the free bird, and hence with the aspiration for freedom. However, since each half of the poem ends with two full stanzas about the caged bird, the overall emphasis of this structure falls on the sorrows of confinement. Angelou further underscores this sorrow by punctuating each half of the poem with an identical stanza that describes the caged bird’s sorrow song.

In addition to this alternating stanza pattern, Angelou also uses another formal strategy to draw out the tension between freedom and confinement. A mere glance at the poem reveals that it contains two different stanza types. Stanzas 1–4 and 6 each consist of seven lines, but each line has an average of just two stressed beats. By contrast, stanzas 4 and 5 have only four lines each, but the lines are twice as long as in the other stanzas, consisting of an average of four stressed beats. This divergence in stanza structure repeats the tension between freedom and confinement in two distinct ways. First, each stanza type internally features a play between short and long. That is, the long stanzas have short lines, and the short stanzas have long lines. Second, the poem’s overall stanza structure oscillates between short and long stanzas. The first three stanzas all have short lines, as if to emphasize the caged bird’s confinement. The stanzas 4 and 5 then feature long lines, as if to reflect the caged bird’s dream of freedom. But this dream is effectively shattered with the final stanza, which returns to the shorter lines.