An updated documented inventory and new records of bird species for the Brazilian state of Maranhao

Herein, we present a checklist of birds from the state of Maranhao, northern Brazil. This region is one of the most heterogeneous areas in the country, comprising upland and flooded rainforests, open vegetation cover types, typical from Cerrado and Caatinga, and mangroves along a wide coastal line (an important route for many migratory birds). Climate is either equatorial with dry winter in the savanna-dominated portion or equatorial monsoonal in the forested part. We compiled from the literature, institutional collections, and virtual databases 14,598 occurrence records, corresponding to 728 species from 88 families and 30 orders. Thus, we add 92 new species to those reported almost three decades ago for the same region. A total of 46 species are endemic to Brazil, 30 represent Amazon forest endemics, 21 are endemic to the Belem Area of Endemism, 11 are endemic to Cerrado, and 9 are Caatinga endemisms. From native and resident species, 33 taxa are considered threatened by national laws. This work fills a gap of knowledge on avifauna diversity and confirms the biological relevance of this ecotone region within northern Brazil. Finally, considering the intensive environmental degradation occurring in the study area and the high number of endemic and threatened species observed therein, we reinforce the need of public policy and civil awareness to engage conservation actions and other activities supporting the maintenance of this biodiversity.