VU
Rio Branco Antbird Cercomacra carbonaria



Taxonomy

Taxonomic note
See C. melanaria. Monotypic.

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - A3c+4c; C2a(i)

Red List history
Year Category Criteria
2024 Vulnerable A3c+4c; C2a(i)
2016 Critically Endangered A3c
2012 Critically Endangered A3c
2008 Near Threatened C2a(ii).
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency medium
Land-mass type continent
Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 56,700 km2 medium
Area of Occupancy (breeding/resident) 1,140 km2
Number of locations 11-20 -
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 6600-16600 mature individuals good estimated 2022
Population trend decreasing poor inferred 2017-2027
Rate of change over the past 10 years/3 generations (longer of the two periods) 15-25% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 25-49% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 25-35% - - -
Generation length 2.81 years - - -
Number of subpopulations 10-20 - - -
Percentage of mature individuals in largest subpopulation 1-89% - - -

Population justification: Extensive playback surveys along the rivers in the Guyanese part of the range found a density of 45 mature individuals/km2 (South Rupununi Conservation Society 2021). Combining this with existing population estimates made by Vale et al. (2007) in the remainder of the species' range in Brazil (where density and occupancy estimates were broadly similar), a global population of c.6,600-16,600 mature individuals was extrapolated (South Rupununi Conservation Society 2021, B. O'Shea in litt. 2022). However, given the data used for estimating the habitat extent and population size in Brazil are 20 years old, an updated assessment is urgently required (South Rupununi Conservation Society 2021, B. O'Shea in litt. 2024). The population structure has not been formally investigated, but the species' absence from areas of suitable habitat suggests that degradation of gallery forest could well mean that there are now numerous small, disconnected populations, where the minimum population size of the largest falls below 1,000 mature individuals.

Trend justification: During surveys along rivers in Guyana, the species was absent from large tracts of seemingly suitable habitat where it had been observed previously (Vale et al. 2007, South Rupununi Conservation Society 2021, B. O'Shea in litt. 2022). It has been hypothesised that the population decline is caused by habitat loss as well as fires degrading and fragmenting habitat, leading to increasing isolation between populations (B. O'Shea in litt. 2022).
Over the past ten years, 7% of tree cover has been lost within the range; since 2017 this has been increasing to a rate equivalent to 10% over ten years (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein). The species may be disproportionately affected due to its strict habitat requirements, as its riverine habitat is easily accessible and thus highly susceptible to forest loss and degradation. To illustrate this, comparable surveys between 2004 and 2021 indicated a range contraction exceeding 50 linear kilometers along the Ireng (Maú) River (B. O'Shea in litt. 2024). Moreover, large parts of the range lie within the footprint of the proposed Bem Querer hydroelectric dam on rio Cotingo (Naka et al. 2020, Aleixo et al. 2023). This is scheduled for completion in 2031 and will flood a significant proportion of the species' habitat, with no prospect for the creation of new suitable areas. Tentatively, rates of population decline are suspected to have been within the band 15-25% over the past ten years, to accelerate to between 25-35% in the ten years from 2017 to 2027 and fall within the band 30-49% for the ten years to 2035 to account for the uncertain impact of the hydroelectric dams.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Brazil extant native yes
Guyana extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Brazil Campinas e Várzeas do Rio Branco
Brazil Lavrados de Roraima

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) suitable resident
Altitude 0 - 100 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation
Natural system modifications Dams & water management/use - Large dams Timing Scope Severity Impact
Future Minority (<50%) Very Rapid Declines Low Impact: 5
Stresses
Ecosystem conversion
Natural system modifications Fire & fire suppression - Increase in fire frequency/intensity Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Ecosystem degradation

Recommended citation
BirdLife International (2024) Species factsheet: Rio Branco Antbird Cercomacra carbonaria. Downloaded from https://datazone.birdlife.org/species/factsheet/rio-branco-antbird-cercomacra-carbonaria on 24/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 24/12/2024.