Distribution and abundance of Pectoral Antwren (Herpsilochmus pectoralis) and Caatinga Antwren (Herpsilochmus sellowi) in the Atlantic Rainforest of northeast Brazil

Abstract

The Pectoral Antwren (Herpsilochmus pectoralis) and Caatinga Antwren (H. sellowi) are thamnophilids endemic to northeastern Brazil. The Pectoral Antwren is considered an “Endangered” species by the IUCN. The present study aimed at providing data on the distribution, abundance, habitat, and conservation status of these species in Rio Grande do Norte state (RN), Brazil, in order to help define conservation strategies for the species. Thirty-three sites in the Atlantic Forest domain were sampled between November 2005 and March 2008, for a total sampling effort of 414 h. Observations took place mainly between 5:30 h and 12:00 h, and records were based on visual and/or auditory detections. Standardized censuses were conducted in four different phytophysiognomies to determine abundance and density. Herpsilochmus pectoralis was found in 73% (n = 24) of the sampled areas, mean density was estimated at 89.1 individuals.km2 and population size was approximately 13,921 individuals for the state. Available area of occupancy was 156.25 km2. Herpsilochmus sellowi was present in 39% (n = 13) of the areas, with mean density of 60.4 individuals.km2, estimated population of 7202 and area of occupancy of 119.25 km2. The population estimate found in this study for H pectoralis is high for a small geographical area, thus demonstrate that BirdLife International information is underestimated. These data widen knowledge of the species at local and national levels, in addition to confirming the importance of H. pectoralis in RN state. The low number of protected areas in the region is alarming, given that privately-owned areas face fragmentation, selective deforesting, burnings and significant real estate development.