Guianan Antwarbler (Hypocnemis cantator): revise global status?

BirdLife species factsheet for Guianan Antwarbler

Guianan Antwarbler (Hypocnemis cantator) occurs in the Guyana Shield of northern South America. It ranges from the extreme east-central Venezuela through Suriname, Guyana and French Guiana to north-east Amazonian Brazil (del Hoyo et al. 2003, Restall et al. 2006). The global population size has not been quantified, but the species is described as fairly common to common, particularly in Guyana and French Guiana (del Hoyo et al. 2003).

The species inhabits the understorey and middle strata of forest edges in terra firme forest, transitional forest and várzea, in treefall gaps as well as in tall secondary woodland. It prefers lowlands, ranging up to 1,300 m in Guyana (del Hoyo et al. 2003). The primary threat to this species is accelerating deforestation, as land is cleared for cattle ranching and soy production, facilitated by expansion of the road network (Soares-Filho et al. 2006, Bird et al. 2011). The species may be particularly susceptible to forest fragmentation (A. Lees in litt. 2011).

Guianan Antwarbler is currently listed as Near Threatened under Criterion A3c, indicating a rapid population reduction in the future (BirdLife International 2019). However, incorporating new information on the rate of forest loss, this species appears to warrant a change in Red List status. Therefore, we present here our reassessment against all criteria for the species.

Criterion A – The population of Guianan Antwarbler was suspected to be in decline by 20-25% over the next three generations based on a model of Amazonian deforestation (Soares-Filho et al. 2006, Bird et al. 2011). However, this analysis has since been repeated using more recent data on forest loss within the range (Tracewski et al. 2016). Tracewski et al. (2016) measured the forest loss within the species’s range between 2000 and 2012 as c. 7,645 km2. This roughly equates to a rate of forest loss of 1% over three generations (14.4 years). The only threat known for this species is forest clearance for agricultural expansion (Bird et al. 2011, A. Lees in litt. 2011). Guianan Antwarbler occurs mostly in the understory along forest borders, in treefall gaps and in secondary woodland (Zimmer et al. 2019). Thus, it may not be as severely affected by deforestation as previously feared. Overall, we can tentatively assume that the population is not declining, but instead stable, and so it does not approach the threshold for Vulnerable under this criterion. Therefore, Guianan Antwarbler may be listed as Least Concern under Criterion A.

Criterion B – The Extent of Occurrence (EOO) for this species is 1,250,000 km2. This is far too large to meet the threshold for Vulnerable (EOO < 20,000 km2). Therefore, Guianan Antwarbler may be listed as Least Concern under Criterion B1. The Area of Occupancy (AOO) has not been calculated and Guianan Antwarbler cannot be assessed against Criterion B2.

Criterion C – The global population size is unknown. Therefore, the species cannot be assessed against this criterion.

Criterion D – The global population size is unknown. Therefore, the species cannot be assessed against this criterion.

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

Therefore, it is proposed that Guianan Antwarbler (Hypocnemis cantator) be listed as Least Concern. We welcome any comments on this 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 its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic.

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

Bird, J. P.; Buchanan, J. M.; Lees, A. C.; Clay, R. P.; Develey, P. F.; Yépez, I.; Butchart, S. H. M. 2011. Integrating spatially explicit habitat projections into extinction risk assessments: a reassessment of Amazonian avifauna incorporating projected deforestation. Diversity and Distributions 18: 273-281.

BirdLife International. 2019. Species factsheet: Hypocnemis cantator. http://www.birdlife.org (Accessed 14 February 2019).

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

Restall, R.; Rodner, C.; Lentino, M. 2006. Birds of northern South America: an identification guide. Volume 1: species accounts. Christopher Helm, London, United Kingdom.

Soares-Filho, B. S.; Nepstad, D. C.; Curran, L. M.; Cerqueira, G. C.; Garcia, R. A.; Ramos, C. A.; Voll, E.; McDonald, A.; Lefebvre, P.; Schlesinger, P. 2006. Modelling conservation in the Amazon basin. Nature 440: 520-523.

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.

Zimmer, K.; Isler, M. L.; Kirwan, G. M. 2019. Guianan Antwarbler (Hypocnemis cantator). In: del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D. A.; de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona, Spain. https://www.hbw.com/node/56806 (Accessed 14 February 2019).

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1 Response to Guianan Antwarbler (Hypocnemis cantator): revise global status?

  1. Red List Team (BirdLife International) says:

    Preliminary proposal
    Based on available information, our preliminary proposal for the 2019 Red List would be to adopt the proposed classifications 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 2019 Red List categories will be published on the BirdLife and IUCN websites in December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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