He actually still exists in some alternate plane, transcending our traditional 4th dimension and incapable of interacting with the physical world he once inhabited. His body laying on the table is just an inaccurate representation of form, like how we might perceive a tachyon.
I mean, i'm not a biologist, but the hummingbird probably has become an ethereal manifestation of his former consciousness, now capable of perceiving the most abstract concepts of existence, time, space, and the lack thereof. But maybe he's just dead because of that damn guarana and caffeine. Idk.