FFX-2: Chocobo Whisperer Achievement
FFX-2: Chocobo Whisperer15
Catch the Amazing Chocobo
To get this achievement you will need to first unlock the "Tricky Trapper" achievement to unlock the chocobo ranch, and capture four chocobos capable of reaching Level 5 (speak to them to check this stat). From here, you need to level them up by dispatching them to the Calm Lands and fighting seven random battles of your own before they will level up. There is a chance a chocobo could run away (minimize this by filling the ranch to capacity), so always save prior to returning to Clasko to check on their status (after the random battles). So in essence: dispatch, fight battles, save, talk to Clasko, and refill hearts/level up - repeat this four times until all the birds are Level 5.
Now you will want to send birds 2-4 to the Calm Lands, fight the random battles, and return again - assuming none ran away, you will find you have discovered a secret dungeon. Entering this dungeon, you will need to navigate it, open all possible doors, and defeat the Anything Eater boss to get to the Amazing chocobo and unlock the achievement. A map for this dungeon to find the boss, all the doors, and the chocobo can be found here.