Spoiler warning: Plot or ending details follow.

The Bird in the Mountains is a Shrine quest in The Legend of Zelda: Breath of the Wild. The quest is obtained from a Rito girl named Molli in Rito Village. When Link speaks with her, she asks if he wants to hear a story. If he answers yes, she will recite a story her grandfather would tell her before bed about a "great white bird" he once saw while climbing a tree in the Hebra Mountains north of the village. She remembers him mentioning something very important about something in the bird's stomach, but confides that she usually falls asleep before hearing what the secret is. She points out the tree to Link as it is visible from where she is perched.

After climbing the tree and looking where Molli said her grandfather saw the bird, Link discovers that it is truly a massive mountainous formation in the shape of a bird. Jumping off the tree and using the Paraglider to glide toward the formation, Mozo Shenno Shrine becomes visible in a small opening. The quest is completed once the shrine is activated.

Completing the quest is not necessary to access the shrine and if it is discovered beforehand, then the quest is accepted and completed simultaneously upon first speaking with Molli.

Spoiler warning: Spoilers end here.