Chocograph piece give you clues about Chocobo Air Garden. It tell you where the shadow that lead you to the Chocobo Air Garden (you need Dead Peppers).

You need to go to these place:

Chocobo Forest (First time) (Yellow Chocobo)
Chocobo Lagoon (First time) (Light-Blue Chocobo)
Chocobo Forest (Second time) (Red Chocobo)
Chocobo Lagoon (Second time) (Dark-Blue Chocobo)
Chocobo Air Garden (First time) (Gold Chocobo)