The leaves that hung but never grew

After I stopped laughing, I wondered: what makes it quite so Goth, in your view? Is it the sheer excess: not just ravens, not just ghosts, but both at once? And the contradictions: they are at the same time insubstantial, vanishing with the dawn, and rather disturbing - what is it that they hunt? What will ease the perpetual famine of a ghost raven? Wilson doesn't say, and no one else, so far as I know, has recorded this belief.