The avian auditory system has become a model system to investigate how vocalizations are memorized and processed by the brain in order to mediate behavioral discrimination and recognition. Recent studies have shown that most of the avian auditory system responds preferentially and efficiently to sounds that have natural spectro-temporal statistics. In addition, neurons in secondary auditory forebrain areas have plastic response properties and are the most active when processing behaviorally relevant vocalizations. Physiological measurements show differential responses for vocalizations that were recently learned in discrimination tasks, and for the tutor song, a longer-term auditory memory that is used to guide vocal learning in male songbirds.