Viability of sex identification of the blue-fronted Amazon parrot (Amazona aestiva) based on iris color sexual dichromatism.

Reintroducing apprehended wild animal in a natural environment is a complex process that involves many steps, including rehabilitating individuals and ensuring viable populations for reproduction; as such, the proportion between males and females to be reintroduced need to be considered carefully. The need of specialized techniques to identify sex on species that do not present discernible sexual dimorphisms can be a hardship to a successful reintroduction. Amazona aestiva, one of the most apprehended species on Brazil, is an example of such case, as sexing techniques employed for it often involves molecular or surgical procedures. Some authors, however, describe potential sexual dimorphisms that could be discernible to the human eye, one of those being an iris color dichromatism between males and females that could present a more conventional way to discern sex on this species. We analyzed the viability of sex identification by direct observation of iris sexual dichromatism, comparing suggestions by professionals familiarized with the species to molecular sexing by Polymerase Chain Reaction (PCR) and measuring color similarity between individuals using digital colorimetry. We found no significant correspondence between sex indication based on direct observation and molecular sexing results, and no relationship between iris color and sex by colorimetric analysis.