You can tell by his silhouette that he's a turkey vulture (note the black body with lighter wings), but you can't really see much of his head, which would be the real giveaway.
They're large birds, with a wingspan of up to 72 inches. They're not raptors; they're scavengers that eat carrion almost exclusively. They summer in our neck of the woods, so it could be that the vulture we saw was either starting his fall migration or getting ready to.
These are not attractive birds, but because they eat carrion it makes sense that their heads would be mostly featherless.
Doodled from this photo.
