Vultures aren't exactly the most aerodynamic of birds to begin with. I'm guessing a humming bird or a wandering albatross wouldn't be quite so care free.
Plus, vultures are scavengers that have to fight to get access to a carcass. What's the slight risk of irepairable feather damage to the certainty of starvation? Also, did they have their wings folded tightly against their bodies while they were prancing and cavorting? In which case, perhaps the most important flight feathers were protected well enough to risk a bit of rough housing.
From what I remember it (It was nearly a week ago now), they had their wingsslightly extended. My guess for this would be that they were trying to cover as much distance with their body as possible, but still keep their flight feathers safe.
Please take this post with a grain of salt (or excess sulphur?). Just playing Devil's advocate.
Of course. :) Peace, Rob AIM: TarryAGoat ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com