It was NOT Maya Angelou who came up with the remark: “I know why the caged bird sings”. It was another authoress, Maya Angelou just “lifted” it and gets all the credit for the remark. I think Maya Angelou “borrowed” that remark for one of her books but never credited the authoress she took it from.
The one thing I liked about “Dr.” Maya Angelou is that in her books she was honest about what a fraud she was.