I like the array of colors and the panning is good. However, I don't feel the centered composition work too well here. A subject like this needs to be shown with a more dynamic composition so the sense of flight come to life. My eyes should flow through the image and not get trapped in the center so something off centered would have been ideal here and maybe a more edgy crop/tilt to heighten the experience further.
Nice capture. This gull looks like a spirit (not that I've actually seen any spirits). The head is slightly over exposed, but I suppose this is not a shot you had too many tries at, besides, it actually contrasts well with the overall darkness of the scene.
kind of static composition, with the bird right in the dead center. placing the bird in the right side of the frame, so that it was flying into the shot would have added some interest.