As of 2005, about 2,600 species and subspecies were known, with the richest diversity in the Oriental (Indo-Malayan) region, followed by the Neotropics.
Most birds found in the Cerrado breed there although there are some Austral migrants (breed in temperate South America and winter in the Amazon basin) and Nearctic migrants (breed in temperate North America and winter in the Neotropics) that pass through.