Zelda Tears of the Kingdom: A White Bird's Guidance Shrine Quest guide to find Wao-os Shrine
Shrine Quests are some of the most fun "bite-sized" sidequests in The Legend of Zelda: Tears of the Kingdom, and one of the most interesting ones is A White Bird's Guidance - A Rito by the name of Laissa found a cave one day when she spotted a "white bird" perched on top of a shadow, early in the morning - but when she went to go look for it again, she couldn't find neither bird nor cave anywhere to be found. Since she mentioned noticing something that sounds suspiciously like a Shrine, it's probably in your best interest to investigate.
How to find the Cave in A White Bird's Guidance
Laissa's hints point to two things; that the "shadow" that the bird in question was perched on was that of Vah Medoh's perch, implying that players should investigate from the top of Rito Village. Secondly, she noticed the bird right after dawn broke. So, grab some flint and wood and be ready to setup a campfire at the top of the perch.
Rest until the morning and then be ready to keep an eye out for the "white bird" she spotted. Track the shadow as it drags across the mountain, and soon enough you'll see where Laissa's misunderstanding arose. The "white bird" she saw was an optical illusion born of a pattern of snow on top of the shadow of Vah Medoh's perch!
Sure enough, if you glide over to the "white bird" you'll find the entrance to your cave in question. Enter the cave and you'll find Wao-os Shrine, with the challenge "Lever Power". This Shrine will challenge you to use physics to catapult a metal ball towards two targets; a little odd that it's not just a freebie for finding the cave, but it makes sense when theoretically you could find the cave even removed from the quest. Congrats on finding the cave - and the Shrine!