Angelou's bird is more hopeful because the bird is caged but has someone on a faraway hill who is listening. The bird longs for freedom, but does not what it is like to have freedom. The caged bird sees what free birds longs to join the free birds. Angelou's bird knows what it wants and it's message is being shared.
Unlike Angelou Dunbar's bird has no one listening to it. The bird is willing to beat its wings against the bars of its cage until they bleed.