Vocalizations of the rare and flagship species Pharomachrus mocinno (Aves: Trogonidae): implications for its taxonomy, evolution and conservation

The Resplendent Quetzal Pharomachrus mocinno is a rare Neotropical bird included in the IUCN red list as Near Threatened. Fragmentation of its habitat, the cloud forest, is considered as the principal threat. Two subspecies are currently recognised but genetic and morphometric studies suggested they could be considered as full species. We assessed whether male vocalisation would support a species delimitation hypothesis. We recorded in the field and downloaded from sound archives vocalisation of 57 individuals from 30 different localities distributed in 11 countries. We estimated the acoustic differences of all the Pharomachrus taxa with multivariate analyses and machine learning techniques. Our results show vocal differences between P. m. mocinno and P. m. costaricensis that could have a molecular basis, potentially due to genetic drift developed during the more than three million years of separation of P. m. mocinno (from Mexico to Nicaragua) and P. m. costaricensis (Costa Rica and Panama). We therefore suggest that P. mocinno could potentially be divided into two species. A possible separation of these taxa into two species could have important consequences for the conservation status of the Resplendent Quetzals, and redirect conservation efforts for these taxa.