"Caged Bird" (written by acclaimed author Maya Angelou in 1969) is one of the most popular and well-known pieces of recent American poetry. Although Angelou is better known for her prose, "Caged Bird" catapulted Angelou into superstardom.
Largely metaphorical, "Caged Bird" follows a bird with clipped wings (i.e. a bird which cannot fly). Despite its physical impairments and its despair, the caged bird continues to be lively and vivacious, still continuing to sing songs of freedom. When the bird finally breaks free, readers learn of its joy as it soars through the sky. However, Angelou then describes another caged bird, a bird which has both its feet tied and its wings clipped. Despite its even worse predicament, that bird still "sings with a fearful trill of things unknown but longed for still and his tune is heard on the distant hill for the caged bird sings of freedom."
In that vein, "Caged Bird" deals with themes of oppression (specifically, how the African Americans were oppressed in the United States), freedom, and the effect attitude has on a person.