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White-masked Antbird Pithys castaneus
BirdLife is updating this factsheet for the 2016 Red List
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A recent rediscovery and three subsequent records at different sites have led to this formerly Data Deficient species being re-evaluated (Collar et al. 1992). It is now classified as Near Threatened, because it is thought to have a moderately small population which is declining owing to habitat loss and fragmentation associated with infrastructure development. The known range is small, but it may well occur more widely. Further data may leads to its downlisting to Least Concern in future.

Taxonomic source(s)
SACC. 2006. A classification of the bird species of South America. Available at: #

Taxonomic note
Gender agreement of species name follows David and Gosselin (2002b).

Pithys castanea BirdLife International (2000), Pithys castanea BirdLife International (2004), Pithys castanea Collar et al. (1994), Pithys castanea Sibley and Monroe (1990, 1993), Pithys castanea Stotz et al. (1996)

Voice Repetitive descending cheeeeurrr calls.

Distribution and population
Pithys castaneus was known from a single specimen collected in September 1937 in the Amazonian forest lowlands, at Andoas on the lower río Pastaza, in what is now Peru. It was rediscovered in July 2001 on the río Morona in western Loreto, northern Peru, and field photographs and specimens were obtained (T. S. Schulenberg in litt. 2002). It has since been found c.116 km to the south-west, near Chicais, Amazonas, a village on the west bank of the Marañon, and has also been collected on the north bank of the Marañon river, east of the Kanpankis Range, south of Tierra Blanca (J. Alvarez in litt. 2007). The type-locality is a source of confusion, but it has recently been suggested that it may refer to the Tunigrama River, which was known for hundreds of years as the Andoas River (T. Mark in litt. 2007).

Population justification
Given its relatively small range and specialised habitat requirements, there are thought to be less than 10,000 individuals, and so it is placed in the band 2,500-9,999 individuals. This equates to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend justification
This species is suspected to lose 2.7% of suitable habitat within its distribution over three generations (18 years) based on a model of Amazonian deforestation (Soares-Filho et al. 2006, Bird et al. 2011). Given the susceptibility of the species to fragmentation and/or edge effects, it is therefore suspected to decline by <25% over three generations.

It is an obligate ant-follower of the understorey of low elevation forest. It was rediscovered in an area of varillal and was thought perhaps to be a white-sand specialist, although it was also twice observed in hilly terra firme, c. 300m from varillal. The second site where it was recorded consists of hilly terra firme on heavily leached, and therefore rather poor, soil.

Rates of habitat loss within its known range are poorly known, but its habitat has been damaged by the construction of an oil pipeline, and several roads are planned. Obligate ant-followers are usually some of the first species to be lost from fragmented forests so this species is likely to be declining due to these pressures.

Conservation Actions Underway
None is known. The west bank of the Rio Morona are part of the Zona Reservada Santiago Comaina, created in 1999 (Lane et al. 2006).Conservation Actions Proposed
Survey outside the Santiago-Marañon-Morona area to determine the extent of its range. Survey terra firme and varillal habitats extensively in the area surrounding the type locality and recent records, to determine its precise habitat requirements. Protect large areas of forest at appropriate sites, in both strictly protected areas and community led multiple use areas.

Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K.

Lane, D. F.; Valqui, T.; Alvarez, J.; Armenta, J.; Eckhardt, K. 2006. The rediscovery and natural history of the White-masked Antbird (Pithys castaneus). Wilson Journal of Ornithology 118: 13-22.

van Oosten, H.; Beunen, R.; van de Meulengraaf, B.; van Noort, T. 2007. White-masked Antbird Pithys castaneus and Orange-throated Tanager Wetmorethraupis sterrhopteron at a new location in Amazonas, Peru. Cotinga 28: 79-81.

Further web sources of information
Detailed species account from the Threatened birds of the Americas: the BirdLife International Red Data Book (BirdLife International 1992). Please note taxonomic treatment and IUCN Red List category may have changed since publication.

Detailed species account from the Threatened birds of the Americas: the BirdLife International Red Data Book (BirdLife International 1992). Please note, taxonomic treatment and IUCN Red List category may have changed since publication.

Explore HBW Alive for further information on this species

Recuento detallado de la especie tomado del libro Aves Amenazadas de las Americas, Libro Rojo de BirdLife International (BirdLife International 1992). Nota: la taxonomoía y la categoría de la Lista Roja de la UICN pudo haber cambiado desde esta publicación.

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Harding, M., Isherwood, I., Mahood, S., Sharpe, C J

Alvarez, J., Lane, D., Mark, T., Schulenberg, T.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Pithys castaneus. Downloaded from on 27/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 27/10/2016.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Near Threatened
Family Thamnophilidae (Antbirds)
Species name author Berlioz, 1938
Population size 1500-7000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 60 km2
Country endemic? Yes
Links to further information
- Additional Information on this species