This is part of the A Legendary Tree of a Legendary Three! quest.
When you’ve triggered the start of the Legendary bird quest, Galarian Zapdos will begin roaming the Wild Area from the base game. Its location can vary, but to keep things simple, we suggest flying to the Meetup Spot (the initial zone) repeatedly until Zapdos spawns in Rolling Fields, up ahead. It should stick out like a sore thumb.
Once you’ve located Zapdos, this is where the fun part begins! Get close enough to Zapdos and it’ll leg it across the Wild Area. That’s your cue to get on your bike and give chase. If you lose sight of Zapdos, don’t worry as its path is predictable–it’ll generally do a simple loop of the zones.
Although it may seem hopeless at first, since Zapdos easily outruns your bike, eventually Zapdos will start to run out stamina (you may notice sweat drops). Keep at it until you finally catch up with Zapdos. Occasionally, Zapdos may stop and turn around, looking puzzled. That’s a good a time as any to make your Legendary acquaintance.
Where possible, avoid fighting Zapdos in zones where there’s hail or sandstorm. If you’re about to catch up with Zapdos in one of these zones, just slow down and “pretend” to chase it, until it reaches the next zone with favourable weather.
Zapdos’s Galarian cousin has exchanged the Electric-type for the Fighting-type. It’s weak to Electric, Ice, Flying, Psychic and Fairy. For attacks, it can use Thunderous Kick, a unique move that lowers Defense, Drill Peck, Reversal and Focus Energy. Its Defiant Ability greatly raises its Attack if you lower one of its stats.
The original Zapdos was objectively the best of the three birds, frequently having a place in high level play, with its great Type combination and defensive stats and moveset. Galarian Zapdos has an inferior defensive typing, but it has a completely different role (now a physical attacker), so it’s apples and oranges really.
To deal with this furious-looking road-runner, you could use a Ghost-type to render its Thunderous Kick useless. Other choices include Psychic or Fairy-types. Drill Peck can be a concern though, but it beats being kicked in the face. Resist the urge to try and lower Zapdos’s Attack, as its Attack stat will end up being higher than it started.
Since Zapdos is no longer an Electric-type, it’s not immune to paralysis. Inflicting paralysis will also slow down the bird and slightly reduce the chances of it attacking–two birds in one stone. Otherwise, it’s the usual Legendary routine–wearing it down with weak moves, then throwing your kitchen sink of Poké Balls at it.