Kaepora Gaebora
A wise sage 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, in fact, the reincarnation of the Sage of Light, Rauru, or in some other way connected to the Spirit Realm-bound sage. 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 OoT helps Link by giving him hints on where to go next.