Vultures are large, flying, non-hostile mobs that populate the skies of desert and temperate worlds (although they're rarer in temperate biomes).
A vulture is basically just an oversized crow. It spawns in the sky, crowds around you, knocks you off whatever you're standing on, and is generally useless and annoying, except for the part where you can sometimes position yourself on top of it and let it carry you around for a bit. It's fun to see how long you can ride a vulture. In a perfect world, we would have vulture saddles.