Coiba Spinetail (Cranioleuca dissita): revise global status?

BirdLife species factsheet for Coiba Spinetail

Coiba Spinetail (Cranioleuca dissita) is endemic to Panama, where it occurs on Coíba Island and Ranchería Island. It inhabits dense undergrowth and vine tangles in forest and forest edge (Ridgely and Gwynne 1989, Angehr and Blewett 2010). The species is described as fairly common. Based on transect data, the population has been estimated to number roughly 14,000-25,000 individuals (Angehr and Blewett 2010), equating to 9,000-17,000 mature individuals. Following the regeneration of formerly cleared areas on Coíba Island, the population is thought to be increasing (G. Angehr in litt. 2020). The species is currently not facing any severe threats. No invasive predators have been found within the range (Angehr and Blewitt 2010), and the entire population is protected within Coíba National Park (G. Angehr in litt. 2020).

The species has been considered Near Threatened, approaching the threshold for listing as threatened under Criterion B1ab(v)+2ab(v) (BirdLife International 2020). However, new information regarding the population size and 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 – The species is thought to be increasing slowly* owing to the regeneration of formerly degraded and converted habitat (G. Angehr in litt. 2020). Therefore, Coiba Spinetail may be considered Least Concern under Criterion A.

Criterion B – The Extent of Occurrence (EOO) for this species is 750 km2. The maximum Area of Occupancy (AOO), as calculated by the total area covered in primary or secondary forest on Coíba and Ranchería, is estimated at 500 km2 (Angehr and Blewett 2010). Thus, the species meets the threshold for Endangered under Criterion B1 (EOO < 5,000 km2) and for Vulnerable under Criterion B2 (AOO < 2,000 km2). To be listed as threatened under Criterion B does require at least two further conditions to be met though.

The species is widespread across the islands of Coíba and Ranchería and can thus not be considered severely fragmented (see IUCN Standards and Petitions Committee 2019). Moreover, as there are currently no substantial threats known to the species, the number of locations** cannot be quantified. Coiba Spinetail does not meet condition a. Neither population size nor habitat availability or range size are undergoing a continuing decline or severe fluctuation, and thus the species does not meet conditions b and c. Overall, even though the EOO is small, the species does not qualify for listing as threatened under either Criterion B1 and B2 and is therefore assessed as Least Concern under these criteria.

Criterion C – The population size is estimated at 9,000-17,000 mature individuals. The population is not undergoing a decline and as such, the species qualifies for Least Concern under this criterion. 

Criterion D – The species’s population size and range are too large to meet the threshold for listing as threatened, and thus Coiba Spinetail may be 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 Coiba Spinetail (Cranioleuca dissita) 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).

**The term ‘location’ refers to a distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, with the size of the location depending on the area covered by the threatening event. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

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

Angehr, G. R; Blewett, C. 2010. Población, reproducción e investigación taxonómica de tres especies de aves amenazadas, en la isla de Coiba. Technical Report, Project PNCOIBA08-017. SENACYT, Panama City, Panama.

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: Cranioleuca dissita. http://www.birdlife.org (Accessed 18 February 2020).

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. www.iucnredlist.org/technical-documents/categories-and-criteria.

IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categoreis and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Ridgely, R.S.; Gwynne, J.A. 1989. A guide to the birds of Panama with Costa Rica, Nicaragua, and Honduras. Princeton University Press, Princeton, NJ, USA.

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2 Responses to Coiba Spinetail (Cranioleuca dissita): revise global status?

  1. 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

  2. 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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