"Blacbird"

The "blackbird" may be symbolic for certain groups/individuals in the society of the time that had previously held back by social standards restrictions. When the song says, "blackbird fly" it could mean that the suppressed peoples should speak out and take to new opportunities, and that "flying" would heighten their quality of life ("fly" has a positive connotation and is associated with freedom). The phrase "light of the dark black night" is symbolizing the promise of changing times. Because "light" has a positive connotation, usually meaning an opportunity, it implies that the "dark black night" (meaning the unknown of the changing times) may hold something good for the "blackbird" or suppressed peoples. All of these symbols come together to create the single effect of hope to those individuals waiting for social change.