Another last last
last minute entry! Yay! (As a matter of fact, it's already 1. December in my corner of the world!) This one is pretty much in the balance as far as violence is concerned, at least in my books... SlyOwl did not specify whether animal violence is tolerated, but I think the contest administrators will go along with it - even though the sight of that seagull exploding is rather gory.
That's a proper idea for a sport though - and it's just what I'd actually
expect seadogs to start practicing, unlike Tereglith here who's pretty sure they can put those times of bloodshed and slaughter behind them and start putting away

So there's a nice combination of originality and realism - likey!
Another advange to this MOC is the usage of the best possible exp
ressions - you didn't need to explain anything, from the sheer violent joy in the pirate lass' exp
ression to the dissatisfied look in that Imperial soldier's face - it's all spot on and even though this might seem like an easy job given the current pattern of minifig face exp
ressions, I still think it's often overlooked. I like how you've handled it here!
As to the seagulls - you've made quite an accurate representation using clips and hands there - kudos for that, I myself enjoy seeing these pieces utilised in an innovative manner. Tereglith's suggestion about using tooth pieces is nice, but I'm not really sure you can actually find a way of connecting those without making the neck look too bulgy - and even if you did, seagulls don't generally have too long beaks, so I think you should keep the current design. Not that you have time to change it anyway...
One thing I'm not certain about is the exploding bird. While I get the blood bursting out of it (and I admit, I'm not overjoyed by the sight... because I actually like seagulls quite a bit), I don't really see the cannonball that hit it. Where is it, has it vanished in thin air / blood? It should be pretty much the size of 2/3 the bird here, but I can't find it anywhere - have you perhaps forgotten to include it? And as to the smoke coming out of the cannon - it's a fine depiction, although I think that using the ice cream cone technique (i.e. piling ice cream cones on top of each other so that they look like smoke) would have looked better here. Another thing you could have used is the interconnecting skeleton arms technique - that way you could have shown the projectile of the cannonball hitting that poor, defenseless, innocent bird (gotcha there, didn't I :P).
To sum it all up - a nice MOC with some very cool touches and a good (albeit bloody) idea. Good luck in the contest!