The avifauna of the Rio Cautário State extractive reserve, Rondônia, Brazil

Abstract The biogeographical province known as the Rondônia Center of Endemism is one of the most threatened regions in the Brazilian Amazon. Here we present a comprehensive assessment of a bird community within this region — that of the Rio Cautário State Extractive Reserve, addressing a major knowledge gap about this Center of Endemism. The reserve lies in the southwestern part of the state wherewe have carrying out bird inventories since 2020 using a combination of direct active searches coupled with passive acoustic monitoring and camera trapping techniques. During our field inventory, we recorded 516 bird species distributed in 73 families. Our avifaunal survey of the reserve represents the most extensive inventory for any site in this region of Amazonia and includes endemic taxa from the Rondônia Center, as well as species threatened with global extinction (nine globally threatened species). This diverse assemblage also includes species vulnerable to hunting and forest-dependent species sensitive to forest loss and fragmentation. These findings underscore the value of using mixed methods in documenting super species-rich avian assemblages.