You're further on than I am, and it happened after I fixed the pond and the bridge in one game, and before I had finished fixing the bridge in another (but i don't play that game every day). Are you SURE there's no kite stuck in a tree near the bridge…? I don't know if the quests occur at set times, or whether they're random, I was just wondering if there was anything to move the story on after fixing up the stone circle (I'm working on opening the cave now, it's the last thing I have to do).
If the kite's not there, then I'm at a loss, presumably you've done the orchid quest, yes…?