Wingull is available in the Mt. Pyre exterior in the tall grass; Routes 105, 106, 107, 108, 109, 119, 122, 134, Dewford Town, Slateport City, Lilycove City, and Sea Mauville while surfing; Routes 103, 104, 110, 115, and 118 in the tall grass OR surfing; Routes 121 and 123 as hordes; and while Soaring. Pelipper is available on Routes 103, 104, 105, 106, 107, 108, 109, 110, 115, 118, 119, 122, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, Dewford Town. Ever Grande City, Mossdeep City, Pacifidlog Town, Slateport City, Sea Mauville, Lilycove City, and the Battle Resort while surfing; Routes 118, 121, and 123 in the tall grass; and while Soaring.
While at first glance Wingull looks like a snack for a hungry Poochyena, if you have the patience to raise it to a Pelipper you'll have a dependable teammate on your hands. It has a good defensive typing with only 2 weaknesses, and good coverage with its dual-STABs. Its movepool is just diverse enough to give some coverage options, and it is granted some key support moves to round it out. Plus, it's basically impossible not to get one (or 5-10 without dupes clause).
Gym #1 - Roxanne (Rustboro City, Rock-type): Unfortunately, this gym is the epitome of a double-edged sword. Water Gun is super effective and very tempting to wield, but both Geodude and Nosepass can OHKO with a crit Rock Tomb (assuming you're at lvl 14). If you have another Pokémon that can put them to sleep with Yawn or Sleep Powder, you'll have a decent chance of wiping them out, but the price for an early wake-up call is steep. Geodude's Sturdy is especially problematic, since you can't get a clean OHKO and start the Nosepass battle with a clean bill of health. Ultimately it's up to you, but if you have better options, I'd suggest you use them.
Gym #2 - Brawly (Dewford Town, Fighting-type): Brawly isn't nearly as dangerous as Roxanne, as neither fighter has a Rock coverage move. Wing Attack probably won't OHKO since Wingull is special-based, but it's doubtful either mon will do much damage while you wait. The only danger is Makuhita getting a few Bulk Ups in, as it makes any switch-in dangerous if you need to get Wingull out.
Rival (Route 110): It's very easy to be overleveled at this point in the game, and if you are, this battle should be fairly quick. Wingull is a great choice for either Grovyle or Combusken with STAB super-effective moves. Even Marshtomp can't do much to it with that Ground immunity coming into play, but be VERY careful of Bide, as it also has enhanced priority in this generation. The other fillers -- Shroomish, Slugma, and Wailmer -- are also not much of a problem, though you probably have a better answer for Wailmer, which also carries Rollout.
Wally (Mauville City): Wingull's Wing Attack disposes of Ralts easily, and its Disarming Voice and Magical Leaf don't do much. This battle should not be an issue.
Gym #3 - Wattson (Mauville City, Electric-type): If you are thinking of using Wingull or Pelipper here, please quit your Nuzlocke now. Thank you.
Tabitha/Shelly (Meteor Falls, tag battle with rival): Pelipper can get a hold of Mightyena once one of them is gone; it is dangerous to try with two, because they could gang up and use Swagger, making Pelipper's Attack skyrocket and the confusion recoil very damaging. Trying it with just one of them is safer though. Numel, Carvanha and Grimer are not a problem, so go ahead, but make sure you already have a Pelipper if you need to fight Koffing, as its Self-Destruct will deal considerable damage.
Tabitha/Shelly (Mt. Chimney): Get 'em with Water Pulse! Except Carvanha, of course, for which Air Cutter is better. Keep in mind that this is only safe if you already have a Pelipper; Wingull does NOT like the possibility of Tabitha's Koffing exploding in its face.
Maxie/Archie (Mt. Chimney): We've moved quite a bit forward in the game at this point. You should definitely have a Pelipper by now, and you're probably noticing the levels are a bit tighter than they were in the beginning. Pelipper is a mediocre choice against Mightyena and Golbat. There are no real dangers here, but both are annoying with Swagger and Confuse Ray respectively, so if you've got somebody that can clean them out quickly, go with that. If you're facing Maxie, Camerupt should fall to a single Water Pulse. Archie's Sharpedo is a lot like the other two...you can face it with minimal chance of a KO, but you probably have better options. Just watch out for Ice Fang if you were thinking of switching in a Grass-type, as it's likely what Sharpedo will be using it against Pelipper.
Gym #4 - Flannery (Lavaridge Town, Fire-type): This could pretty easily be a 3HKO battle, assuming you're about 2-3 levels over. Fortunately Slugma, Numel, and Torkoal are all fairly slow so you can probably manage to move first and Water Pulse them into oblivion. Torkoal is capable of taking one hit if you’re unlucky and your IVs and EVs aren’t properly in place, so be wary of the sun.
Gym #5 - Norman (Petalburg City, Normal-type): PROTECT IS YOUR FRIEND. My suggestion would be to spam Protect on the turns his Slaking is attacking, and use Stockpile to beef up early. This keeps you from needing to risk a switch out for the Vigoroth. If for some reason you get off with your Protects or something, just watch out for Retaliate... that hurts.
Courtney/Matt (Southern Island, tag battle with Steven): Pelipper should fare well in this battle, if it manages to drown Camerupt with one Surf and leave only Koffing on the other end of the battlefield. Sharpedo, instead, has Swagger, and it could become dangerous in the long run, so much of it will depend on whether or not it uses it and if so, what happens to your confused Pelipper. Thanks to its good Defense, if Sharpedo is out of the way, taking on Grimer should not be a problem with enough patience.
Tabitha/Shelly (Weather Institute): Only one team member on each end, Camerupt for Tabitha and Sharpedo for Shelly. Drown Camerupt with any Water move and hope Sharpedo doesn't go for Swagger, which will make things difficult, but otherwise Pelipper can handle it with good Flying moves.
Rival (Route 119): Second verse, same as the first. Grass and Fire poses no threat, nor does Water but you probably have better options.
Gym #6 - Winona (Fortree City, Flying-type): Pelipper isn't bad here since there are no super effective moves in the house, especially against Skarmory which is annoying unless you have a special Electric or Fire attack. But if you've got someone super effective against the gym they'll finish the battle much more quickly. Pelipper vs Pelipper can take an especially long time.
Courtney/Matt (Mt. Pyre): They only have Camerupt or Sharpedo, depending on the version. Camerupt is easy as pie for Pelipper's Surf, while Sharpedo is a bit tougher, but Pelipper's Defense makes it viable if you have Air Cutter or Air Slash.
Rival (Lilycove City): The newcomer Swellow doesn't pose a threat, but as before if you've got something super effective it'll be faster. Otherwise it's more of the same.
Courtney/Matt (Lilycove Hideout): Much like the previous matchup, Camerupt is very easy, and Sharpedo is doable with special Flying STAB. They still have the same "team".
Gym #7 – Tate and Liza (Mossdeep City, Psychic-type): Solrock and Lunatone may both be Psychics... but they're also Rock-type, which puts us back in the same boat as Roxanne way back in the first gym. Unfortunately, Pelipper's base 65 Speed is going up against Lunatone's and Solrock's base 70, so if you do plan on using Pelipper you definitely want a few levels or a ton of Speed EVs. Not to mention Surf won't OHKO at equal levels either. If you have to use Pelipper, remember that Surf hits your allies in this generation and that Solrock should die first because it can hit you harder than Lunatone. All in all, I'd leave Pelipper out unless you don't have other options, as a non-Flying Water-type or Dark-type will serve you better.
Maxie/Archie (Seafloor Cavern): Pelipper is about the same as before for this battle. It's bulky enough not to get OHKO’d so it's safe, but you probably have better options for everything except Maxie's Mega Camerupt. There are no super effective moves floating around so feel free to switch Pelipper in as needed.
Gym #8 – Wallace (Sootopolis City, Water-type): Yet another episode of safe-but-you-probably-have-better-options. There are a couple Ice Beams out there that'll do normal damage, but nothing really threatening. Feel safe switching Pelipper in and healing up your main players if you need to, but I wouldn't try to win this battle on Pelipper's Air Cutter. Toxic is an option, but not ideal if you have a better choice.
Wally (Victory Road): Do yourself a favor and go to Sea Mauville once you get Dive. The Ice Beam TM will totally be worth it, I promise. Wally leads with Altaria, and a good Ice Beam will do it in (and Cotton Guard can't do anything about it!). From there, Delcatty is meh and Roselia is easy pickin's. There's really no sweeping though, thanks to Magneton. Mega Gallade isn't a bad matchup though, especially if you've got Rain Dance up and use Hurricane. Overall, Pelipper is fairly useful for this fight.
Elite Four Sidney (Ever Grande City, Dark-type): If you've got a STAB super-effective move, Pelipper is basically obsolete for this battle. Otherwise, Pelipper can wreck Shiftry and Cacturne, and the others don't pose too much of a threat as there are no Electric or Rock moves lurking around. Be careful of setting up Rain Dance though, as Sharpedo can hit your teammates hard with it.
Elite Four Phoebe (Ever Grande City, Ghost-type): Phoebe is a bit more of a threat than Sidney for Pelipper. Sableye has Power Gem and more importantly, Dusknoir has all of the elemental punches, including Thunder Punch. Stay away from those two and the battle becomes, once again, ok-but-you-probably-have-better-options.
Elite Four Glacia (Ever Grande City, Ice-type): If you use Pelipper here the battle will probably drag on forever. The first Glalie has Light Screen which will severely nerf Pelipper's potential, and the second Glalie has FREEZE DRY. STAY AWAY. One more time... Pelipper is alright, but you probably have better options.
Elite Four Drake (Ever Grande City, Dragon-type): Finally Pelipper can lend a good hand. Besides Kingdra, Ice Beam will hit everyone for monster damage (double weaknesses everywhere!). The only problem is speed. It's all going to depend on how overleveled you are. Mostly watch for the first Flygon's Rock Slide and Salamence's Thunder Fang, and if you don't think you'll outspeed, don't risk it.
Champion Steven (Ever Grande City, Steel-type): Pelipper is also decent against the champ. Skarmory can't do much but poison you (try holding a Pecha Berry), and your Surf hits its modest Special Defense stat. Try to set up a Rain Dance against it to power up Surf. Claydol, Armaldo, and Aggron are all weak to Surf and should be OHKOs with Rain Dance up, but Aggron and Armaldo are packing Rock moves, and Aggron is especially threatening due to carrying Sturdy, so be wary. Luckily they're also slow. Cradily is also dangerous due to STAB Ancient Power and Ice Beam won't OHKO it, so at that point it should be time to retire Pelipper unless you're getting desperate. Mega Metagross is unfortunately out of Pelipper's league, but Surf, especially Rain-boosted, can do moderate damage in a pinch.
Wingull will begin with Growl and Water Gun when you catch it. Supersonic and Wing Attack come soon after at 5 and 8 respectively. Mist is useless, but Water Pulse at 15 will be your STAB move of choice until you get Surf much later. You will generally want Quick Attack over Growl at 19, and Air Cutter replaces Wing Attack at 22. You're set here until after you evolve and get Protect, which is all but mandatory for Norman. Stockpile is an option if you want to get rid of Quick Attack/Supersonic and/or use Pelipper more defensively, but Swallow and Spit-Up aren't really worth it. Fling and Hydro Pump come next but have little use. Tailwind at 50 can be very useful depending on your team makeup, but leaving a spot for Ice Beam, or perhaps Rain Dance, is generally wiser. Finally at level 55 you get Hurricane, which has perfect accuracy in the rain and is much stronger than Air Cutter.
There's not a whole lot of use in the TM section minus the already mentioned Ice Beam and Rain Dance. Blizzard can go over Ice Beam if you're looking for more power but the accuracy drop is scary. Roost is cool but unnecessary if you can use items. Scald is great if you have someone else using Surf, as it's only 10 BP lower than Surf and has a decent chance at a burn. If you get one with an egg move, distinctly possible given how many times you encounter it in the game, you likely won't be keeping it until the end of the game. Gust is useful early game until you get Air Cutter, and Aqua Ring might get used on occasion as would Twister, but they just aren't strong enough to use by mid- to late-game.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
Wingull Line Ratings
What Nature do I want? Anything that lowers Attack will be helpful if not a bit annoying early game with Wing Attack. Special Attack raising natures are great too, and something that lowers Speed isn't a total letdown given Pelipper's middling Speed stat.
Which Ability do I want? Keen Eye is the only ability you can get in the wild. Wingull’s Hidden Ability is Rain Dish, which can be situationally useful as well, since the recommended set uses weather.
At what point in the game should I be evolved? Evolve it as soon as possible. Pelipper does not naturally learn Air Slash, but it is not worth waiting for, as Air Cutter will suffice and Wingull is too frail to survive in the late game, even with Eviolite.
How good is the Wingull line in a Nuzlocke? Wingull will be a pleasant surprise. Their lack of weaknesses and decent bulk make them dependable and good dual STAB give them nice options in a lot of battles.
Weaknesses: Rock, Electric (x4)
Resistances: Fighting, Bug, Steel, Fire, Water
Neutralities: Normal, Flying, Poison, Ghost, Grass, Psychic, Ice, Dragon, Dark