Final answer:
The caged bird in Maya Angelou's poem is miserable because of the cage, as inferred from its restricted existence in contrast to the free bird's freedom.
Step-by-step explanation:
The inference that can be made about the caged bird in Maya Angelou's poem is that the caged bird is miserable because of the cage. This can be inferred from the contrast between the caged bird's restricted and confined existence and the free bird's ability to claim the whole sky and fly all over. The caged bird's yearning for freedom and its inability to escape the cage suggests its misery.