The geographic and seasonal potential distribution of the little known Fuertes’s Oriole Icterus fuertesi

Abstract

SummaryEndemic species and those with restricted distribution ranges are a priority and national responsibility for global conservation. Fuertes’s Oriole Icterus fuertesi is a Mexican endemic species and is perhaps one of the least known birds in the country. It has traditionally been regarded as conspecific with the Orchard Oriole I. spurius, but recently it has been suggested that it is a distinct species, causing concern about its risk status. There is a scarcity of information related to the geographic and seasonal distribution of Fuertes’s Oriole, as well as a lack of information regarding its abundance and habitat preferences. We gathered all the available records, and used ecological niche modelling to analyse the spatial and temporal patterns of the distribution of the species. We also carried out field surveys in the surroundings of known locations of the species in order to determine its abundance. We found that the species is narrowly and locally restricted to the surroundings of eight localities along the Gulf coast of Mexico that constitute small and discontinuous areas of presence. We also found no evidence of migration to the Pacific Coast in winter, as has been historically thought. Instead, our results suggest that the species exhibits a short-distance migration, with northern populations migrating to the southern range along the Gulf coast of Mexico. Analysis of abundance and field observations confirm that the species is restricted to highly modified wetland landscapes associated with urban and semi-urban habitats. Based on these results, we suggest the urgent reassignment of its risk category.