They were barred from most educational and economic opportunities enjoyed by whites. Dunbar uses the analogy of the caged bird and nature outside to the situation that black people faced in the 1890's. Blacks had been emancipated in 1863, but they did not achieve equality with white people for another century. Black people did not have the same opportunities as whites and were seen as inferior. The caged bird sees tantalizing images of nature right outside the bars, but it cannot escape.
Nature is off limits to the caged bird.
At the turn of the century, America is growing and prospering. Immigrants are flooding the country, building their fortunes. Everywhere, ordinary common people are becoming millionaires. The standard of living is rising astronomically. New inventions, such as the automobile, telephone, electric lights, and motion pictures were springing up daily and people were building their fortunes off these inventions.