Archived 2016 topics: Rusty-backed Spinetail (Cranioleuca vulpina) is being split: request for information on C. dissita.

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for passerines

Lynx Edicions and BirdLife International will soon publish the second volume of the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.

The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.

Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.

The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 2 of the checklist (for passerines) will begin to be incorporated into the 2016 Red List update, with the remainder to be incorporated into subsequent Red List updates.

Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.

Rusty-backed Spinetail Cranioleuca vulpina is being split into C. vulpina and C. dissita, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, Cranioleuca vulpina was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criteria. C. vulpina  (as now defined following the taxonomic change) is found throughout South America in a range of habitats including riparian thickets, gallery forest, river-island scrub and other water-edge habitats (Remsen 2016). In general this species is considered ‘fairly common’ (Stotz et al. 1996), but the population size and any trends have not been quantified. However, in the absence of any known substantial threats to this species, this species is not thought to approach the threshold for Vulnerable under any criteria, and so it is proposed that it be listed as Least Concern.

C. dissita is endemic to the island of Coiba, Panama, in forest and forest edge habitats (Remsen 2016). It is highly range restricted, with an Extent of Occurrence of c.665 km2; and while it is considered ‘fairly common’ on the island (Remsen 2016), introduced predators may be causing a population decline, and its limited range makes it vulnerable to large scale threats such as hurricanes (del Hoyo et al. 2003). With no further information this species is likely to qualify as Near Threatened under criterion D2, having a highly restricted range within which future threats could drive a rapid (but not extremely rapid) population decline within a short space of time. However, if there is any further information on population sizes and whether invasive species or habitat loss are causing a population decline this species would likely qualify as Endangered under criterion B1ab(v) and possibly C2a(ii).

Comments are invited on these proposed categories and further information would be welcomed.



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

Remsen, J.V., Jr. 2016. Rusty-backed Spinetail (Cranioleuca vulpina). 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. (retrieved from on 12 September 2016).

Stotz, D. F., Fitzpatrick, J. W., Parker, T. A. and Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. 2010. Quantitative criteria for species delimitation. Ibis 152: 724–746.


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1 Response to Archived 2016 topics: Rusty-backed Spinetail (Cranioleuca vulpina) is being split: request for information on C. dissita.

  1. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 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 of 28 October, 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 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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