Level-Up
Based it off of Skarmory. I also attempted to make a level-up pool that would work well and make sense ingame, providing it with the amazing SonicBoom at level 9 to make it useful early on, Steel Wing at 23, a time where SonicBoom won't really cut it anymore, Acrobatics at 28 to give it very powerful ingame STAB, Bullet Punch at 31 for priority utility (around this level, that starts becoming a real concern), and finally Belly Drum at 50, around the time the player faces the final gym and gets ready for the E4, providing Cawmadore with a useful niche for endgame.
Egg Groups
Flying is pretty obvious - it's a bird. Field is for two reasons - one, many Flying types find themselves in the field group, with Cawmadore's attractiveness and charisma finding it capable of mating with a lot of pokemon, and two, it prevents Cawmadore from having egg move illegalities, which are unnecessary.
Moves
Attacking
Aerial Ace
Nearly universal among anything that can perform some sort of cut or slash.
Acrobatics
Competitive: At the level of power we're talking for BD sweeps, Acrobatics is coverage, able to break through everything sans Cawmadore's staunchest checks, like Heatran. Which is extremely helpful, because otherwise Hippowdon, Rotom-W, and Landorus-T can stop it a bit easier, something Cawmadore would really NOT like to be the case given that it's so hard to get a sweep off with it.
Return
Universal TM
Frustration
Universal TM
Hidden Power
Universal TM
Facade
Universal TM
Drill Peck
Well, yeah, bird, beak, self-explanatory.
Iron Head
Cawmodore are known for being quite hard-headed, both in an argument, and in a fight, possessing a fierce headbutt that can leave quite the bruise.
Bullet Punch
Competitive: Cawmodore would really like some priority to handle scarfers if need be as well as provide a secondary role outside of belly drumming (poor man's revenge killer). The downside if, of course, Steel is awful at coverage, and you don't gain access to recovery.
Brick Break
Competitive: Brick Break was added due to Fighting coverage being necessary if we wish to avoid being completely walled by Steel and Electric types, while chosen over Drain Punch because Drain Punch's healing is...well, quite frankly, too good on Cawmodore.
Surf
Pirate captain bird should know how to navigate the seven seas! It only makes sense!
Flash Cannon
Cawmodore is very shiny, and capable of using that shininess as a weapon.
Payback
Anyone who dares harm Cawmodore or his crew will find that it is capable of harboring quite a grudge, and will seek payback tenfold for every feather harmed.
Air Slash
Wings. Duh.
Night Slash
Bird can slash with wings. Mostly because Skarmory also learns it.
Pursuit
Trying to escape from a pirate captain bird? Good luck with that. Cawmodore will pursuit you to the very depths of Davy Jones Locker if it must.
Fake Out
Cawmodore possesses such an intimidating presence that it is even capable of faking out its foes, causing them to stagger in confusion.
Sky Drop
Cawmodore possesses intense strength, and is capable of hefting a foe up into the air, slamming it back down to the ground for massive damage.
Sky Attack
If two blows won't do the trick, Cawmodore is capable of charging up for a massive attack that can leave even the mightiest of foes staggered.
Swift
Both steel types and flying types tend to learn Swift, it only makes sense to give it to Cawmodore.
Rock Smash
Skarmory can break rocks, why can't Cawmodore? Big meaty bird fists smash puny stones!
Slash
See: Night Slash
Steel Wing
Cawmodore has pretty sharp, powerful wings, capable of smashing foes down left and right. Kind of a gimmie.
Final Gambit
If the fight is looking against against it, Cawmodore will slam into the opponent in a last ditch Final Gambit to attempt to take them down.
Hyper Beam
Almost every final evo stage learns this, and de facto, Cawmodore is the final evo, regardless of how many stages it might have.
Giga Impact
See above.
Fly
Duh.
Metal Claw
Sharp claws on the end of its wings? Yeah.
Retaliate
Again - harm a single feather on the head of Cawmodore's crew, and it will return with furious vengeance tenfold! Or in this case, twofold.
SonicBoom
It isn't quite fast enough for ExtremeSpeed, but Cawmodore can still go fast enough to create a pretty solid SonicBoom. See: Floatzel.
Peck
Bird, beak, peck peck peck.
Horn Drill
With a horn that sharp, it's no surprise Cawmodore is capable of knocking out its opponent with a single, well placed attack - though, due to the precision required, it is a risky gambit, as a miss will leave Cawmodore open to counter-attack without fear of harm.
Supportive
Belly Drum
yes.
Toxic
Universal TM (That really doesn't make a whole lot of sense...)
Substitute
Universal TM
Protect
Universal TM
Sleep Talk
Goes with Rest, Universal TM
Rest
Universal TM
Roost
Competitive: Roost is a reliable option for recovery that enables Cawmodore to stay healthy throughout the match, and gives it a second shot at a Belly Drum, as it were. 4MSS, of course, but on the right team Roost can be very handy.
Encore
Competitive: Encore's a pretty cool, if somewhat niche option to help Cawmodore set up.
Rain Dance
Sailor bird, yeah? Seems like it'd be able to do a rain dance pretty well.
Knock Off
Competitive: Gimmick move, mostly. Still, it might give Cawmodore some use outside of Drumming, like how Bullet Punch can let it revenge.
Attract
Cawmodore is VERY attractive. It's a captain pirate bird, of course it'd know how to make the ladies/guys swoon!
Round
Universal TM
Swagger
Universal TM
Endure
It doesn't matter how heavy the burden is, or how much hurt gets thrown Cawmodore's way. If it needs to hold out for just one more turn, the iron will of the captain will pull through, Cawmodore refusing to faint no matter what, just to hold out.
Defog
Captain bird, yeah? If there's ever troublesome fog upon the seas, with a mighty gust of its wings, Cawmodore can clear the fog away.
Flash
That shiny metal capable of pulling off Flash Cannon could very easily perform Flash.
Follow Me
Distracting its opponents with a shiny gleam of its coat and a few choice, taunting words, Cawmodore can force them to attack it instead, shielding its crew from blows. After-all, what noble captain is not willing to put their very HP on the line for their crew?
Helping Hand
Like any good captain, Cawmodore knows how to rally its crew, giving them a Helping Hand to boost their attacks to new heights of power.
Leer
Cawmodore has such an intimidating presence that it is no surprise that a Leer from it would make even the staunchest of foes shake in their boots.
Lock-On
Cawmodore lets no foe escape, no matter what. Once it has Locked-On to its opponent, not even escaping to the mists of the sea will aid them, for Cawmodore will not let them avoid it.
Double Team
Universal TM
Snore
Nearly-universal tutor
Notable Exclusions
Sand Attack
While almost every bird gets it, Cawmodore is above such petty tactics. It will fight its opponent honorably, without resorting to such cheap tricks.
Brine
I don't really see how Cawmodore would perform this. Precisely five non-water types learn Brine - of them, one is a ice bear, one is Mew who learns every TM (it was a TM in gen 4), one of them is Lugia, a pokemon with very heavy ties to the sea and a legendary, one of them is a sweaty, salty wrestler with so much salt it even has a move named SmellingSalt, and the last one is god.
Beat Up
Yeah, this one seems obvious with my flavor. "Cawmodore has a crew, why not attack with it?" Despite that, though, Cawmodore is honorable. It fights its opponents one on one, like any proper captain with honor would - for only cowards and honor-less wretches gang up on an opponent that deserves an honorable duel.