<p>Categorization is a cognitive process which generates the ability to perceive similar but not identical stimuli as equivalent. In order to classify an object into a category, an animal must learn to recognize the key features of the novel object using the experience gained from previous interactions with similar objects. Thus, categorization eliminates the need to examine each novel object afresh, significantly expanding the adaptive capabilities of the organism. The ability to categorize is inherent in animals with different types of nervous system structure. This review addresses fundamental approaches to the study of visual categorization in birds, which have outstanding capacities for this process. Analysis of extensive data obtained from studies of visual categorization in different models in birds not only opens up the possibility of identifying the general biological neural bases and mechanisms underlying this process, but can also be used to expand the neuromorphic properties of artificial intelligence systems.</p>