macbeth, looking out of the window, is trying to see himself as a murderer and can only see himself in the position of the crow: that his day of power now is closing; that he has to distinguish himself from the other rooks by a difference of name, rook-crow, like the kingly title, only; that he is anxious at bottom to be one with the other rooks, not to murder them; that he can no longer, or that he may yet, be united with the rookery; and that he is murdering banquo in a forlorn attempt to obtain peace of mind.