Conservation practices and the formation of vocal dialects in the endangered Puerto Rican parrot, Amazona vittata

Abstract

Captive breeding is a conservation strategy that often results in behavioural changes in animals born and reared in captivity. Culturally transmitted behaviours, such as learned vocal signals, are particularly prone to the effects of captive breeding because captive animals have limited opportunities to learn these behaviours from wild animals. Changes in learned behaviour could affect the success of reintroduction programmes once captive animals are released into the wild. We tested for vocal divergence of learned calls in Puerto Rican parrots, Amazona vittata. We recorded parrots from two captive populations and two wild populations, representing all extant populations of this species. We also recorded parrots that had been translocated between populations and evaluated changes in their vocal signals over time. Fine-scale acoustic analysis revealed vocal divergence in all four populations. The geographical variation in vocal signals evolved over a time span of 10–40 years, demonstrating that cultural traits can evolve rapidly in managed parrot populations. Parrots that were translocated between populations adopted the new vocal signals. Vocal divergence in this species likely resulted from a combination of historical rearing practices, cultural drift and geographical separation. Managers should consider strategies to facilitate the acquisition of foreign vocal signals prior to release.