The perception of self in birds

The perception of self is an important topic in several disciplines such as ethology, behavioral ecology, psychology, developmental and cognitive neuroscience. Self-perception is investigated by experimentally exposing different species of animals to self-stimuli such as their own image, smell or vocalizations. Here we review more than one hundred studies using these methods in birds, a taxonomic group that exhibits a rich diversity regarding ecology and behavior. Exposure to self-image is the main method for studying self-recognition, while exposing birds to their own smell is generally used for the investigation of homing or odor-based kin discrimination. Self-produced vocalizations - especially in oscine songbirds - are used as stimuli for understanding the mechanisms of vocal coding/decoding both at the neural and at the behavioral levels. With this review, we highlight the necessity to study the perception of self in animals cross-modally and to consider the role of experience and development, aspects that can be easily monitored in captive populations of birds.