Spiny-faced Antshrike (Xenornis setifrons): revise global status?

BirdLife species factsheet for Spiny-faced Antshrike

Spiny-faced Antshrike (Xenornis setifrons) occurs from eastern Panama to north-western Colombia. Its range is disjunct, particularly in Colombia, where the species has only been recorded in the Serranía del Darién and the Serranía de Baudó (Adsett and Wege 1998, Renjifo et al. 2016, Schulenberg 2020). It inhabits the understory of humid foothill forest, mostly on steep slopes or in ravines (Adsett and Wege 1998). The species is found at elevations of 120-800 m, but mostly above 350 m (Adsett and Wege 1998).

Due to its high forest dependence, Spiny-faced Antshrike is at risk of habitat loss through logging of forests for agricultural purposes. However, the human population is low over large parts of its range, where threats are consequently considered minimal (P. Salaman in litt. 1999, Schulenberg 2020).

Spiny-faced Antshrike has been considered Vulnerable under Criteria B1ab(i,ii,iii,v); C2a(i) (BirdLife International 2020). However, new information regarding the population trend suggest that this species may warrant a change in Red List status. Therefore, we have fully reviewed the species here against all Red List criteria.

Criterion A – Spiny-faced Antshrike is undergoing a moderate decline (Partners in Flight 2019). The only threat known to this forest-dependent species is habitat loss; however forests within the range remain largely unaffected by human activities (P. Salaman in litt. 1999, Schulenberg 2020). Over the past ten years (one generation length being 3.0 years; Bird et al. 2020)*, forests within the range have been lost at a rate of <2% (Tracewski et al. 2016, Global Forest Watch 2020). Population declines are therefore presumably very slow, not exceeding 5% over ten years. The species is therefore listed as Least Concern under Criterion A.

Criterion B – The newly calculated Extent of Occurrence (EOO) for this species is 54,000 km2. The maximum Area of Occupancy (AOO), as calculated by a 4km2 grid over the area of mapped range, is c.8,500 km2. These values are too large to warrant listing as threatened under Criterion B, and Spiny-faced Antshrike is therefore considered Least Concern under this criterion.

Criterion C – The population of Spiny-faced Antshrike has preliminarily been estimated at 6,000-15,000 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, this meets the threshold for listing as threatened under Criterion C. However, to do so a species must meet further conditions.

The species is suspected to be in slow decline. A suspected decline however precludes a listing as threatened under Criterion C. The rate of decline is unlikely to exceed 5% over ten years, and subcriterion 1 is not met. We have no information on the subpopulation structure, but it is likely that the species forms two subpopulations: The northern subpopulation from Panama to the Colombian Darién, which likely contains the majority of mature individuals, and a smaller subpopulation in the Serranía de Baudó in the south. Subcriterion 2a is therefore not met. We have no evidence to suggest that the population is undergoing extreme fluctuations, and subcriterion 2b is not met either. Overall, the species does not fulfil enough conditions to warrant listing as threatened or Near Threatened under Criterion C. Spiny-faced Antshrike is therefore considered Least Concern under this criterion.

Criterion D – The population numbers 1,500-7,000 mature individuals. Assuming that the true population size is closer to the lower end of the estimate, Spiny-faced Antshrike may be considered Near Threatened, approaching the threshold for listing as threatened under Criterion D1.

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 Spiny-faced Antshrike (Xenornis setifrons) be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion D1. 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

Adsett, W. J.; Wege, D. C. 1998. Natural history of the little-known Speckled Antshrike Xenornis setifrons. Cotinga 10: 24-29.

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: Xenornis setifrons. http://www.birdlife.org (Accessed 5 May 2020).

Global Forest Watch. 2020. Interactive Forest Change Mapping Tool. http://www.globalforestwatch.org (Accessed 5 May 2020).

Partners in Flight. 2019. Avian Conservation Assessment Database, version 2019. http://pif.birdconservancy.org/ACAD.

Renjifo, L. M.; Amaya-Villarreal, A. M.; Burbano-Giron, J.; Velasquez-Tibata, J. 2016. Libro rojo de aves de Colombia, Volumen II: Ecosistemas abiertos, secos, insulares, acuaticos continentales, marinos, tierras altas del Darien y Sierra Nevada de Santa Marta y bosques humedos del centro, norte y oriente del pais. Editorial Pontificia Universidad Javeriana e Instituto Alexander von Humboldt, Bogota, Colombia.

Schulenberg, T. S. 2020. Spiny-faced Antshrike (Xenornis setifrons), version 1.0. In: Schulenberg, T. (ed.). Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.spfant1.01 (Accessed 5 May 2020).

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 Spiny-faced Antshrike (Xenornis setifrons): 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 ten years approximately 1.3% of tree cover with >30% 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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