Archived 2016 topics: Blue Vanga (Cyanolanius madagascarinus) is being split: list C. madagascarinus as Least Concern and C. comorensis as Endangered?

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.

Blue Vanga Cyanolanius madagascarinus is being split into C. madagascarinus and C. comorensis, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, C. madagascarinus was listed as Least Concern under on the basis that it did not approach the threshold for Vulnerable under any criterion. C. madagascarinus (as now defined following the taxonomic change) is widespread throughout forest in Madagascar (Schulenberg 2013). It is considered common (Morris and Hawkins 1998), and is not thought to approach the threshold for any criteria for Vulnerable. Therefore, it is proposed that this species be listed as Least Concern.

C. comorensis is only found in forest on the islands of Mohéli (where it is common) and Grand Comore in the Comoros (Schulenberg 2013). However, there appears to be some debate over the presence of the species on Grand Comore, and it is considered extinct on this island by some (Schulenberg 2013; Yamagishi and Nakamura 2016). Its Extent of Occurrence is currently 2,000 km2, incorporating the possible Grand Comore population. While this species can be found in a variety of wooded habitats (Yamagishi and Nakamura 2016), native forest is threatened and continues to be altered (Safford and Hawkins 2013). If the number of locations* this species is found is confirmed to be ≤5, this species would qualify as Endangered under criterion B1ab(iii).

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

*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. 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).

References:

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

IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.

Morris, P.; Hawkins, F. 1998. Birds of Madagascar: a photographic guide. Pica Press, Robertsbridge, UK.

Safford R. J. and Hawkins, A. F. A. (2013). The Birds of Africa. Vol VIII: The Malagasy Region. Christopher Helm, London.

Schulenberg, T. S. (2016) Blue Vanga Cyanolanius madagascarinus. Pp. 815-817 in Safford R. J. and Hawkins, A. F. A. (eds). The Birds of Africa. Vol VIII: The Malagasy Region. Christopher Helm, London.

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.

Yamagishi, S. and Nakamura, M. (2016). Blue Vanga (Cyanolanius madagascarinus). 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 http://www.hbw.com/node/60565 on 9 September 2016).

 

James Westrip and Rob Martin (BirdLife International)

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2 Responses to Archived 2016 topics: Blue Vanga (Cyanolanius madagascarinus) is being split: list C. madagascarinus as Least Concern and C. comorensis as Endangered?

  1. Phil Gregory says:

    Comments from my Comoros trip in Dec 2014 below, I would have thought EN is appropriate, we did not find it on Grand Comore.
    Comoros Blue Vanga Cyanolanius comorensis bensoni 4 at Djando, Mohéli Dec 9 and 1 Dec 10, very like Madagascar Blue Vanga but more lilac blue and looked longer billed. Tom saw an additional 2 here on Dec 9, and Omar has reported up to 12 at this
    site. Considered conspecific with Madagascar Blue Vanga by most authorities but split by Sinclair and Langrand based on larger size, subtle colour differences and different bill shape. Race bensoni from Grande Comore is possibly extinct, making this a Mohéli endemic. Call very similar to Madagascar birds, see XC.

  2. 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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