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Allpahuayo Antbird Percnostola arenarum
BirdLife is updating this factsheet for the 2016 Red List
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This recently described species is known from a small range, within which the extent and quality of its highly specialised habitat are declining. This combination of factors qualifies it as Vulnerable.

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

10 cm. A small, sexually dichromatic antbird. Male dark grey with black throat and wing coverts (the latter fringed with white). Female has dark grey upperparts with black wing coverts (fringed reddish-brown), and underparts reddish-brown and white. Similar spp. Male lacks black crown of Black-headed Antbird P. rufifrons, and female shows strong contrast between reddish-brown of majority of the underparts and clear white belly patch, chin and throat. Voice Song a series of similar notes that decelerate in pace (especially initially).

Distribution and population
Percnostola arenarum is known only from Loreto in Peru, from the drainage of the Rio Nanay west to the Rio Tigre, including Nauta on the bank of the Rio Maranon between those two rivers (Isler et al. 2001). The Nauta specimen, at the Museum of Natural History, had previously been tentatively assigned to P. rufifrons jensoni (Capparella et al. 1997).

Population justification
The population is estimated to number 1,000-2,499 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.

Trend justification
This species is suspected to lose 7% of suitable habitat within its distribution over three generations (14 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.

P. arenarum is found in dense, stunted terra firme forest on white sandy soil (a habitat named 'varillal' by local people), with an understorey dominated by the saplings of white sand specialists. It appears to be restricted to this habitat type, although it was also found, albeit extremely locally, in a nutrient-poor habitat termed 'irapayal' comprising taller forest with a dense understorey of irapay palm, which grows on very old, weathered clay soils as well as sandy soils (Isler et al. 2001).

Based on current knowledge about this species, it has a very specialised habitat niche and a very small geographic range. The habitats in which it is found are subject to intense human activity in a region of rapid population growth. Varillal is heavily exploited for poles for building houses, and the leaves of the irapay palm are extensively harvested to make thatched roofs (Isler et al. 2001). The impact of these threats is exacerbated by the fact that the species has only been found in certain 'varillales', and even fewer 'irapayales', despite intense ornithological surveying (Isler et al. 2001). Despite protection, 200 people have entered the reserve (see Action) and carved out homesteads, illegal hunting occurs, and illegal road building and logging destroys habitat (J. Alonso Alvarez in litt. 2003).

Conservation Actions Underway
The establishment of the Zona Reservada Allpahuayo-Mishana in 1999, which includes much of the known range of P. arenarum, was a critical step in the protection of this species. This must be followed by the resources required to manage the area (Isler et al. 2001) and enforce existing legislation. Conservation Actions Proposed
Protect in practice as well as legally the areas of habitat in which it is found from destruction and heavy exploitation. Assess the full extent of this species range and population size.

Capparella, A. P.; Rosenberg, G. H.; Cardiff, S. W. 1997. A new subspecies of Percnostola rufifrons (Formicardiidae) from northeastern Amazonian Peru, with a revision of the rufifrons complex. Ornithological Monographs 48: 165-170.

Isler, M. L.; Alonso, J. A.; Isler, P. R.; Whitney, B. M. 2001. A new species of Percnostola antbird (Passeriformes: Thamnophilidae) from amazonian Peru, and an analysis of species limits within Percnostola rufifrons. Wilson Bulletin 113: 164-176.

Further web sources of information
Explore HBW Alive for further information on this species

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

Text account compilers
Benstead, P., Harding, M., Sharpe, C J, Symes, A.

Alonso Alvarez, J.

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

Recommended citation
BirdLife International (2016) Species factsheet: Percnostola arenarum. Downloaded from on 24/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 24/10/2016.

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.

Additional resources for this species

ARKive species - Allpahuayo antbird (Percnostola arenarum) 0

Key facts
Current IUCN Red List category Vulnerable
Family Thamnophilidae (Antbirds)
Species name author Isler, Alvarez Alonso, Isler & Whitney, 2001
Population size 600-1700 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 7,700 km2
Country endemic? Yes
Links to further information
- Additional Information on this species