In West Clock Town (WCT), there is an owl statue which the developers placed past the steps leading down to South Clock Town (SCT). This owl statue is here to give the illusion that when you look down the steps, you can see the owl statue from SCT.
However, the SCT and WCT maps are of course completely different maps, and so the owl statue you see in SCT and the owl statue you can see past the steps in WCT are completely different owls. Since the WCT owl statue can't normally be accessed or activated, it has been dubbed the 'Hidden Owl statue' or 'Hidden Owl'
The Hidden Owl cannot be soared to as it has no index on the song of soaring map, saving at the Hidden Owl will place the player in the Mayor's Residence (the default map of the game) upon re-loading the file.