Assessing population size of the Chestnut-Capped Foliage-Gleaner

Abstract

Chestnut-Capped Foliage-Gleaner (Hylocryptus rectirostris) is a Neotropical ovenbird species (Furnariidae) endemic to gallery forests of the Cerrado region of central Brazil. While it is not considered globally threatened, the degree of habitat loss occurring throughout much of its known distribution may warrant its inclusion on red lists beyond just the state of Sao Paulo. The primary objective of this study is to evaluate the conservation status of Chestnut-Capped Foliage-Gleaner according to those criteria adopted by the IUCN. Results of censuses conducted in the Serra do Cipó National Park were used to estimate the entire population size of the Chestnut-Capped Foliage-Gleaner and refine our understanding of its actual geographic distribution. Census results indicate that the species has a population density of 3.8 pairs/100 ha and occupies only a quarter of its preferred habitat in the study area, which is well below the carrying capacity. The total population size estimate, accounting for its entire extent of known occurrence, is just over 54,000 pairs. The geographic distribution and total population size estimated in this study do not indicate that the Chestnut-Capped Foliage-Gleaner should be considered a threatened species according to IUCN criteria. However, it was not possible to evaluate this species conservation status based on information concerning population fluctuations over time, another of the IUCN criteria. Nonetheless, the rate of habitat destruction in the Cerrado during the last century has certainly resulted in a population decline of greater than 10%, a factor sufficient enough to warrant its inclusion in the IUCN category of vulnerable.