Kaepora Gaebora
A wise owl that roams the skies of Hyrule. Although his appearance renders him harmless, this owl knows more than anyone in Hyrule. He will often aid Link in his quest and guide him in the path to defeat evil.
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 Spirit Realm-bound sage, but later on in the game he talks to Link as a child in the Spirit Temple and says that he found it hard to believe that Link could travel in time. In the alternate dimension of Termina, the wise owl has a counter-part known as Kaepola Gaebola, who teaches Link the Song of Soaring.
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 around Hyrule, similar to the ones in Link's Awakening, was a homage made to him by the game's designers. Also, the totem pole in Renado's sanctuary looks like him.
Kaepora Gaebora himself makes a reappearance in Four Swords Adventures, serving much the same role he did in Ocarina of Time.
He is also known for making long speeches, much to some gamers' annoyance.