What is the main idea of this poem?

I think that the main idea or themes deals with freedom is power. The opening stanza describes in lyrical imagery the sheer elation of freedom. The uncaged bird—the free bird—sails on a current of wind and become a portrait of unfettered energy and ambition. The colors of the sky are vivid, and the wind is comparable to forces of a river sweeping downstream. But what really seals the deal is the kicker that comes at the end with the concept that such freedom to fly when and where one wants gives the bird the confidence to dare “to claim the sky.” In the closing image of that opening stanza and the similar conclusion to the fourth stanza when the uncaged bird “names the sky his own” the speaker is making a tangible connection between freedom and power. They are inextricably related; impossible to separate one from the other.