Dan, cool angle and full wingspread captured. Im not sure what the food item is, but its always good to see something in their beaks. I also like the inclusion of the OOF foliage in the BG. If this were mine, I would probably move the gull a little more up into the URC.
I like the diagonal pose and the beautiful BG. Interesting morsel in the bill, perhaps a piece of vegetation (BTW, I like the faint water trailing off of it). I agree with Stuart's composition suggestion...you could also alternatively add back left and bottom if you have it.