Figure of speech used by Maya angelou in her poem why the bird cage sing?

In her poem "I Know Why the Caged Bird Sings," Maya Angelou employs metaphor as a central figure of speech. The caged bird symbolizes individuals who are oppressed and constrained, while the free bird represents those who experience liberty and opportunity. Through this contrast, Angelou powerfully conveys themes of freedom, confinement, and the struggle for self-expression. The imagery of the birds serves to highlight the emotional and psychological impact of oppression on the human spirit.