Yeah invite Clasko on to your ship by talking to him once before going towards the headquarters in Mushroom Rock in Chapter 1. Then after the mission return to Mushroom Rock and talk to him and agree to invite him on your ship. Drop him off at the Calm Lands and then go to the old monster arena to complete the mission there. After that talk to him inside to get some greens. After you get greens you can catch Chocobos, just throw greens at it before it runs away and kill all the monsters then feed it more greens at the end if the battle doesn't end. You may get lucky and get a chocobo all by itself in battle or you could get unlucky and find a chocobo that helps the enemies and even worse cast meteor on your party if you don't feed it fast. It might even cast meteor after you feed it if it likes you enough. Sometimes if it likes you a lot it'll cast meteor twice.