This shot remind me of "Valiant". The way you have composed the shot and captured the sudden movement is impressive. If you can post process and give some more brightness to the shot it will improve.
You are going to hate me, but my comment is a combination of all of the above. :-)
As said above, I like the crispness and the focus. The detail level is very good, and the framing really is excellent. In my opinion, instead of brightening it up, I think you should give it a different twist. Try either making the entire image or just the city backdrop (and sky if it is easier) b&w. I don't think it should be taken away, just muted. If you want to tweak the contrast, it may be a smidgen more appealing to look at. I am not sure if you have a "remove background lighting" tool or not, but if you do, applying it a bit would make the image appear a bit more dismal and all that much mroe emotional.
Nice capture. If you make any of these changes, let me see it! If you don't feel like it, can I give it a try (even if the changes are slight)? Either way, my email address is in my profile.
I think this is such a great shot! It's fantastic that you were able to take an "action" picture of these two gulls..and I believe the only thing I would change, and it would be very easy to do, is to crop them, to have only the wooden pilings showing and the gulls...and then frame it maybe..with a black background on each side along with a tiny border line of grey or white. I think the skyline takes away from "zero-ing" on the gulls..as strange as that may sound..but they deserve total attention, its such a wonderful photo!!!