Zelda Spirit Tracks Hidden Tasks/Games part #8

After you play the game for a while you should get a letter from Ferrus. It shows a snapshot of where he is. He so happens to be lost in the lost woods, how ironic. Now go find him, he should be by a whistle sign. Find that sign and you'll find Ferrus. Once you get there he says he wants you to take him to the ocean temple to take some photos. Once you get there he says thanks and gives you a force gem. The spirit tracks should be complete soon.