Since the birds and the man are the primary subjects here showing more sky and less grass/scrub I think would improve the image. Breaking the rule of thirds here I think would work very well.
Nice moment. I like the mystery of your composition too - the hiding behind bushes feel. I think it could use more contrast in processing - the detail that's visible in the foreground grasses or whatever isn't really useful compared to what more contrast might achieve in the shapes of the gulls and the man.