Birds are the clearest symbol of freedom in the novel. The mobility and adaptability that flight allows birds gives them a level of freedom that the humans in the story lack. Walter loves birds. He is endlessly fascinated by their personalities, their lack of cruelty, and their independence. During the section on mountaintop removal, Walter tries to protect the habitat of the cerulean warblers, but only in novel’s final section is he able to act, which directly and immediately benefits the local birds. He tries to constrain the neighborhood cats by making bibs for them. He also tells Linda Hoffbauer that “this land belonged to the birds before it belonged to us” (543). When he visits Jessica, he says that birds are “the only thing that's still lovely to me” (553). Despite their freedom, birds still require protection from external forces of which they are unaware. When Walter and Patty donate their home and make it an aviary sanctuary, it is clear that the birds require captivity in order to survive their freedom.

It is also significant that the Cerulean warblers migrate. The characters in Freedom all suffer from various forms of restlessness. Their instincts periodically steer them towards motivations that they do not consciously understand at all times, similar to the ways in which a Cerulean warbler knows when it is time to migrate.