Kaepora Gaebora
Kaepora Gaebora is wise owl that roams the skies of Hyrule in The Legend of Zelda: Ocarina of Time. Although he appears to be a simple owl, he seems to know more than anyone else in Hyrule. He often aided Link in his quest, guiding him on the path to defeat evil through his long speeches.
Among the theories revolving around Kaepora Gaebora is the idea that the owl is the reincarnation of the Sage of Light, Rauru, or in some other way connected to the sages, but later on in the game he talked to Link as a child in the Spirit Temple saying that he found it hard to believe that Link could travel in time, which makes it seem as though there may not be any connection. In the alternate dimension of Termina, the wise owl has a counterpart known as Kaepola Gaebola, who taught Link the Song of Soaring and led him to the Lens of Truth.
In Link's Awakening, an owl similar to the one from Ocarina of Time helps Link by giving him hints on where to go next. Although he doesn't appear in Twilight Princess, some think that the Owl Statues scattered around Hyrule, similar to the ones in Link's Awakening, was a homage made to him by the game's designers. Eldin, the Light Spirit of the Eldin Province, is also an owl.
Kaepora Gaebora himself makes a reappearance in Four Swords Adventures, serving much the same role he did in Ocarina of Time.