AbstractStereotypies are abnormal repetitive behaviors that often develop in animals housed in impoverished environments. Stereotypy represents the interaction of several complex developmental phenomena. To characterize the temporal nature of stereotypy increase (escalation) and decrease (attenuation), we monitored changes in stereotypy performance in young Orange‐winged Amazon parrots reared either in barren cages or cages provided with enrichments designed to facilitate foraging and locomotion. Unenriched parrots developed significantly more stereotypy than enriched parrots, and the mean time to stereotypy onset and the rate and magnitude of stereotypy increase also differed between the two groups. We then provided enrichment to the birds that had been reared in the barren cages. Following a 4‐week delay, stereotypy was significantly reduced. These results show that stereotypy can be both prevented and reversed with appropriate environmental modification and illustrate how studying this behavior at many points over time can provide insights into its ontogeny. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 209–218, 2004.