Unknown Animal

I don't know what that little Grayish-Blue shape in the middle of the photo is. My guess is either a Whale or a Seal, but I suppose it could also be a Bird, or even a rock.
This photo was taken on the coast of Puget Sound in Seattle.

Looks like a Great Blue Heron in flight.

It's definitely a large heron flying away from the camera, so Great Blue sounds right.

@Chlidonias Great Blue is the only large dark heron in Washington, so not really any other species it could be!