When do you get Bart the tinker to help you in viva pinata to help you release the ponocky from the cage?

In "Viva Piñata," you can get Bart the Tinker to help you release the Ponocky from the cage after you've completed the necessary quests to unlock him. Specifically, you need to have the Ponocky in your garden and ensure that you have a sufficient amount of Tinkering resources available. Once these conditions are met, you can call upon Bart to assist in the release. Afterward, he will perform the required task and free the Ponocky from its cage.