I've Got the Power
This area is not necessary to finish the game storyline, but it's important to fill the Pokédex. The Power Plant is a huge maze containing many kinds of rare items and electric-type Pokémon, including the winged mirage Zapdos. Just be careful. Some of the "rare items" are actually Electrodes waiting to attack.
If you just want to catch Zapdos now, bring Max Repels, which only work on basic Pokemon and do not affect legendaries.
To those who started with Squirtle or Charmander, Zapdos will be very much worth the effort of catching with the long sea routes ahead. Bring lots of ultra balls (they can be purchased in Fuchsia City) and some healing items; save the master ball for a much tougher foe ahead. As with any legendary, save before battling Zapdos. If you KO it, it will not appear again.
Zapdos knows drill peck, thunder wave, detect, and agility.
Pokemon
| FireRed | Level | Encounter Rate | LeafGreen | Level | Encounter Rate |
|---|---|---|---|---|---|
 Magnemite
|
22-25 | 30% | Magnemite
|
22-25 | 30% |
 Voltorb
|
22-25 | 30% | Voltorb
|
22-25 | 30% |
 Pikachu
|
22-26 | 25% | Pikachu
|
22-26 | 25% |
 Magneton
|
31-34 | 10% | Magneton
|
31-34 | 15% |
 Electabuzz
|
32-35 | 5% | |||
| Special Pokémon | |||||
 Zapdos
|
50 | Only one | Zapdos
|
50 | Only one |