When I first saw the Silhouette not too long ago, that's the first type that ran through my mind, a Flying/Electric type. The only other type Pokémon that had that was Zapdos, who's a legendary Pokémon. It'd be cool to have a non-legendary take role of that duo type again. On the other hand, it could be another legendary for this generation being revealed early.Kinda looks like Spearow but I'm sure it's an eagle. Would be awesome if it was Flying/Electric.
However, my mind has also drifted to the possibility of it being the region's main bird Pokémon's third stage in evolution. If so, then it's going to be pretty sick and possibly one of the best designed Pokémon for a region's Flying type.
I'm going with the Eagle/Griffin thought though. From it's large look and feathers nearing the claws, it can take that aspect I'd think.