zelda-skyward-sword
In Skyloft, there is bird-like statue with a ruby for its right eye, with nothing in its left. It is located on the top of the rock platforms that traverse the left side of the small lake, on the way up to the waterfall cave. Does this statue have a purpose?
I've noticed that the statue rotates depending on whether it is day or night, but is that the only thing it does?
To be able to get the chest that shows at the circled location, you'll need the Clawshots. Head toward the entrance of the Waterfall Cave. To your left, you should see a floating island just above you with some vines hanging on the side. Use the Clawshots on the vines to grab it and climb up on. Keep climbing until you reach the highest point, the island with the waterfall. You can reach the chest then by jumping to the island that has it.
They serve no purpose, they are just merely the skylights for the houses they are above. Notice at night, it is a lot brighter from the outside. That's because of the lights inside shining out. If you look from the inside, it should be pretty clear that they are skylights:
Skylights at night from inside Kukiel's house
They are probably all designed that way to go with the Skyloft theme of having fans (and fan-shaped objects) everywhere.
Best Answer
It's relevant to the games story, so you don't need to worry about it for now. However, if you really want to know...
late game spoiler warning