Archived 2016 topics: Blue-headed Fantail (Rhipidura cyaniceps) is being split: list R. sauli as Least Concern or Near Threatened?

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-headed Fantail Rhipidura cyaniceps is being split into R. cyaniceps, R. sauli and R. albiventris, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, Rhipidura cyaniceps (BirdLife species factsheet) was listed as Least Concern as it was not considered to approach any of the thresholds for listing as Vulnerable under any of the criteria. The pre-split species was characterised as common in most of its range and inhabited a wide range of wooded habitats from sea level to 2,400m (Boles 2016).

R. cyaniceps (as defined following the taxonomic change) is found on Luzon and Catanduanes, R. sauli is restricted to the island of Tablas, and R. albiventris is found on Ticao, Masbate, Panay, Guimaras and Negros.

Both the new nominate R. cyaniceps and R. albiventris are suggested to be listed as Least Concern, as following the changes they still do not appear to approach the thresholds for listing as Vulnerable under any of the criteria.

Tablas Fantail R. sauli has a newly calculated extent of occurrence of only 950km2. If the species occurs at roughly similar densities to those recorded for R. albiventris on Negros Island (115-220 inds/km2 [Evans et al. 1993]) then the population is estimated at 20,000-49,999 individuals. On the island of Tablas roughly 4% of tree cover appears to have been lost within the last 15 years (Hansen et al. 2013), from which a minor, slow ongoing population decline in the species is inferred.

Consequently R. sauli is suggested to be listed as Least Concern, as although the species has a restricted range it is not considered severely fragmented or to occur at a limited number of locations*, there is not believed to have been or to be a significant population reduction, and the population is considered likely to be relatively large. If there is evidence that this species occurs at much lower densities than were recorded for R. albiventris on Negros then the species may be Near Threatened, as it may approach the thresholds for listing as Vulnerable under criterion C2a(ii).

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:

Boles, W. (2016). Blue-headed Fantail (Rhipidura cyaniceps). 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/59142 on 6 October 2016).

Evans, T. D., Dutson, G. C. L. & Brooks, T. M. eds. 1993 Cambridge Philippines Rainforest Project 1991 Final Report. ICBP Study Report No. 54. Cambridge: BirdLife International

Hansen, M. C., P. V. Potapov, R. Moore, M. Hancher, S. A. Turubanova, A. Tyukavina, D. Thau, S. V. Stehman, S. J. Goetz, T. R. Loveland, A. Kommareddy, A. Egorov, L. Chini, C. O. Justice, and J. R. G. Townshend. 2013. High-Resolution Global Maps of 21st-Century Forest Cover Change. Science 342: 850–53. Data available on-line from:http://earthenginepartners.appspot.com/science-2013-global-forest. Accessed through Global Forest Watch on 6th October 2016. www.globalforestwatch.org

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.

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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6 Responses to Archived 2016 topics: Blue-headed Fantail (Rhipidura cyaniceps) is being split: list R. sauli as Least Concern or Near Threatened?

  1. Mike Crosby says:

    Allen (2006 Forktail 22: 77-84) said “This species was fairly common in native forest in the Balogo-Dobdoban region, and it was also seen on Tablas Peak”. Much of Tablas is cultivated with only small areas of forest remaining, and if this species is confined to forested habitats its population might be much lower than estimated above. Tablas Drongo, the other species endemic to the island, is Endangered. I suggest ask Des Allen about this species.

  2. Des Allen says:

    Thanks Mike. What does ‘extent of occurrence’ mean? You don’t define it here and my internet connection is too slow here in the Philippines to check.
    If you mean its probable historical pre human range, then all of Tablas is probably correct. Currently I would expect its breeding range to be restricted to the Balogo watershed, and other mature/semi-mature natural forest that may exist. Much forest on the island is Gmelina or suchlike and I never saw this fantail in such habitat.

  3. Des Allen says:

    I doubt it inhabits more than 100km2 but I intend to go back and check when time permits

  4. Rob Martin (BirdLife International) says:

    Thank you for the comments.
    Extent of Occurence is calculated as a Minimum Convex Polygon around species locations for the species. In this case it encompassed the entire island as the map was quickly and crudely ‘cut’ out of the parent species. It doesn’t necessarily relate to the area of occurrence, which is the area actually used by a species.
    It is clear that the species has a far lower habitat tolerance than that which the initial rapid assessment was based. Certainly the population estimate should therefore be revised down considerably given the habitat information. Actual forest on Tablas is rather limited, and certainly that suitable for the application of the density estimate from Negros for R. albiventris appears to be more like 50km2. This would imply that the population, even if the species occurs at 115 per square kilometer, would likely be well below 10,000 mature individuals.
    Coupled with the ongoing suspected slow population decline it is therefore considered that Tablas Fantail should be listed as Vulnerable under criterion C2a(ii).

  5. Rob Martin (BirdLife International) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2016 Red List would be to list Tablas Fantail as Vulnerable under criterion C2a(ii).

    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 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.

  6. Bob Natural says:

    I have birded this 2016 (March) in Tablas and visited San Agustin, particularly in Long Beach and Dobdoban and in both areas, Tablas Fantails were seen.

    However, for Tablas Drongo, I have not seen/heard the said species in Long Beach but seen and heard them in Dobdoban.

Comments are closed.