Category perception, as Herrnstein (1990) defined it, is a powerful and pervasive cognitive ability possessed by every species in which it has been adequately tested. We have studied category perception of vocal communication signals in songbirds for over 20 years. Our first studies provided us with an understanding of songbird vocal category production and perception, clarifying perceptual categorization and the underlying mechanisms. More recent work has moved towards understanding functional vocal categories such as sex, dominance, species, and geography. Some of our most recent work has moved into the realm of conceptual knowledge, with studies aimed at understanding birds’ ability to deal with concepts of sameness and danger (i.e., threat level). Here we provide key examples that effectively show the wide range of abilities possessed and used by songbirds.