Pale-billed Antpitta (Grallaria carrikeri): revise global status?

BirdLife species factsheet for Pale-billed Antpitta

Pale-billed Antpitta (Grallaria carrikeri) is endemic to Peru, where it occurs on the east side of the Andes, south and east of the Río Marañón, from central Amazonas to southern La Libertad (del Hoyo et al. 2003, Schulenberg et al. 2007). The species is described as uncommon to fairly common (Stotz et al. 1996, Schulenberg et al. 2007). Assuming that the species occurs at the same density as a congener, Variegated Antpitta G. varia (3 mature individuals/km2; Santini et al. 2018), Pale-billed Antpitta might number c. 90,000 mature individuals. It inhabits the floor and undergrowth of humid montane forest with dense stands of Chusquea bamboo, in elevations of 2,300-3,100 m (del Hoyo et al. 2003, Schulenberg et al. 2007).

Due to its strict forest dependence, Pale-billed Antpitta is sensitive to the loss, conversion and degradation of its forest habitat. Deforestation has been widespread in the northern Andes of Peru, as forests are cleared for timber extraction and the establishment of plantations or cattle pastures (Barnes et al. 1995, Davies et al. 1997). However, most of this activity concentrated in lower areas outside of the species’s range, with higher altitudes only partly affected (García-Moreno et al. 1997, D. Lebbin in litt. 2012).

Pale-billed Antpitta has been considered Near Threatened under Criterion B1ab(i,ii,iii,iv,v) (BirdLife International 2020). However, this is no longer tenable because this was based on an Extent of Occurrence (EOO) value calculated as the ‘area of mapped range’. This is no longer appropriate and the EOO should be calculated using a Minimum Convex Polygon (see IUCN 2001, 2012, Joppa et al. 2016), as EOO is a measure of the spatial spread of areas occupied by a species, not the actual area it occupies. The resulting EOO value now exceeds the thresholds required to maintain the species’s current listing, and as such it potentially cannot retain its current Red List status. Therefore, we have fully reviewed the species here against all criteria.

Criterion A – The population trend for this species has not been directly estimated. However, deforestation data from between 2000 and 2012 (Tracewski et al. 2016) suggests that forest loss within the range has been negligible (< 1% over three generations or 15.1 years*). Given that the only threat known to the species is forest loss, the population has likely been stable over the last three generations. Therefore, Pale-billed Antpitta is assessed as Least Concern under Criterion A.

Criterion B – The newly calculated Extent of Occurrence (EOO) for this species is 49,000 km2. This is too large to meet or approach the threshold for listing as threatened under Criterion B1; therefore, the species may be considered Least Concern. The Area of Occupancy (AOO) has not been quantified following IUCN Guidelines (IUCN Standards and Petitions Committee 2019), and the species cannot be assessed against Criterion B2.

Criterion C – The global population size is too large to warrant listing as threatened under this criterion, and therefore Pale-billed Antpitta is considered Least Concern under Criterion C.

Criterion D – The global population size and range are too large to warrant listing as threatened under this criterion, and therefore Pale-billed Antpitta is considered Least Concern under Criterion D.

Criterion E – To the best of our knowledge, there has been no quantitative analysis of extinction risk conducted for this species. Therefore, it cannot be assessed against this criterion.

Therefore, it is suggested that the species be listed as Least Concern. We welcome any comments to the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’ Red List status. Therefore, please make sure your comments are relevant to the species’ Red List status and the information requested. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Barnes, R.; Butchart, S.; Clay, R.; Davies, C.; Seddon, N. 1995. The conservation status of the Cordillera de Colán, northern Peru. Cotinga: 6-7.

Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International. 2020. Species factsheet: Grallaria carrikerihttp://www.birdlife.org (Accessed 17 February 2020).

Davies, C. W. N.; Barnes, R.; Butchart, S. H. M.; Fernandez, M.; Seddon, N. 1997. The conservation status of birds on the Cordillera de Colán, Peru. Bird Conservation International 7: 181-195.

del Hoyo, J.; Elliott, A.; Christie, D. 2003. Handbook of the Birds of the World, vol. 8: Broadbills to Tapaculos. Lynx Edicions, Barcelona, Spain.

García-Moreno, M. J.; Tibosch, J. H.; Ballón, G. 1997. Estado de conservación de la avifauna de la Cordillera Colán, Departamento de Amazonas, Perú.

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. Available at: www.iucnredlist.org/technical-documents/categories-and-criteria.

Joppa, L. N.; Butchart, S. H. M.; Hoffmann, M.; Bachman, S. P.; Akçakaya, H. R.; Moat, J. F.; Böhm, M.; Holland, R. A.; Newton, A.; Polidoro, B.; Hughes, A. 2016. Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation Biology 30: 362-370.

Santini, L.; Isaac, N. J. B.; Ficetola, G. F. 2018. TetraDENSITY: A database of population density estimates in terrestrial vertebrates. Global Ecology and Biogeography 27: 787-791.

Schulenberg, T. S.; Stotz, D. F.; Lane, D. F.; O’Neill, J. P.; Parker III, T. A. 2007. Birds of Peru. Princeton University Press, Princeton, NJ, USA.

Stotz, D.F.; Fitzpatrick, J.W.; Parker, T.A.; Moskovits, D.K. 1996. Neotropical Birds: Ecology and Conservation. University of Chicago Press, Chicago, USA.

Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.

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3 Responses to Pale-billed Antpitta (Grallaria carrikeri): revise global status?

  1. Red List Team (BirdLife International) says:

    Global Forest Change data on tree cover loss up to 2019 have now been released and made available via Global Forest Watch. Based on these data, over three generations (15.1 years) approximately 2.6% of tree cover with 75% canopy cover was lost from within the species’s range (Global Forest Watch 2020). This does not affect the above assessment under Criterion A.

  2. Red List Team (BirdLife International) says:

    The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you,
    BirdLife Red List Team

  3. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information, our preliminary proposal for the 2020 Red List would be to adopt the proposed classification outlined in the initial forum discussion.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from those in the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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