Zapdos is one of the few Legendary Pokemon that can be found within Pokemon FireRed, being one piece of the Kanto Legendary Bird Trio. Zapdos will most likely be the second or even third Legendary Pokemon you encounter within the game, since you have to backtrack to Cerulean City some time after obtaining HM Surf. Zapdos can actually be found at the end of the Power Plant, which is located within Route 10 (east of Cerulean City near Rock Tunnel) but only accessible when you have the ability to traverse waters. The Power Plant is a small building full of Electric Type Pokemon and Trainers using similar Pokemon, being pretty easy to maneuver through since one room leads to the next. Zapdos awaits at the far end of the Power Plant.
Zapdos will be found at Level 50, and it will know the moves Thunder Wave, Agility, Detect, and Drill Peck. Since Drill Peck is Zapdos' only attacking move, it's really the only thing you will need to worry about. Since Flying Type Moves aren't effective against Rock Type Pokemon (as well as dual Rock/Ground Types), they are usually the way to go when facing this Legendary Bird. Zapdos is also an Electric/Flying Type Pokemon, meaning its especially weak to Rock Type Attacks and Ice Type Attacks.
When looking to catch Zapdos, always save directly before proceeding to battling the Legendary Bird. It's never fun when you accidentally defeat Zapdos or if it defeats all of your Pokemon, but all of that is avoidable simply by saving directly before trying to catch it. Also, don't forget to purchase loads of Ultra Balls and Repels from the Poke Mart before going to catch Zapdos. Repels will help you avoid facing Wild Pokemon leading up to Zapdos in the Power Plant, and Ultra Balls are the best possible Poke Balls you can use when trying to catch Zapdos (since it's not worth using your one and only Master Ball on).
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