Archived 2016 topics: White-cheeked Nuthatch (Sitta leucopsis) is being split: request for information on S. przewalskii.

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.

White-cheeked Nuthatch Sitta leucopsis is being split into S. leucopsis and S. przewalskii, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, S. leucopsis was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. S. leucopsis (as now defined following the taxonomic change) is found in forest (particularly coniferous or mixed forest) in north-east Afghanistan, and the Himalayas of Pakistan, India and Nepal (Harrap 2016a). It is considered common to fairly common throughout its range apart from Nuristan in Afghanistan where it is ‘relatively scarce’ (Harrap 2016a). It is not thought to be under any immediate threat and is not thought to approach the threshold for Vulnerable under any criterion. Therefore, it warrants listing as Least Concern.

S. przewalskii is found across central China; in Sichuan, east and central Qinghai, the extreme south-west of Gansu, and extreme north-east of Xizang, with separate populations in south east Xizang and central Yunnan (Harrap 2016b). The species has been both described as rare (Harrap 2016b) and uncommon (MacKinnon and Phillipps 2000), and Harrap (2016b) has suggested the lack of confirmed recordings may warrant the species to be listed as Data Deficient, Near Threatened or Vulnerable. However, the species does seem to have been recorded well (see eBird webpage http://ebird.org/ebird/map, and xeno-canto webpage http://www.xeno-canto.org/). Forest loss within the species’s range appears to be relatively low (see Hansen et al. 2013) and so without any clear evidence for an alternative significant threat or to suggest a population decline, the population may be assumed to be stable. Its range size is sufficiently large to not approach the threshold for Vulnerable; and even using population density estimates below that of congeners and assuming only a proportion of the species’s range is occupied, the population size is likely to be greater than 1,000 mature individuals (the threshold for listing as Vulnerable on population size alone). Therefore, in the absence of any further information this species likely qualifies as Least Concern.

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

References:

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 10th October 2016. www.globalforestwatch.org

Harrap, S. 2016a. White-cheeked Nuthatch (Sitta leucopsis). 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/59930 on 10 October 2016).

Harrap, S. 2016b. Przewalski’s Nuthatch (Sitta przewalskii). 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/59931 on 10 October 2016).

MacKinnon, J. and Phillipps, J. 2000. A Field Guide to the Birds of China. Oxford University Press, Oxford, UK.

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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2 Responses to Archived 2016 topics: White-cheeked Nuthatch (Sitta leucopsis) is being split: request for information on S. przewalskii.

  1. James Eaton says:

    Given the large areas of coniferous forest found through western Sichuan to northern Qinghai and southern Gansu, and its tolerance of degraded forest (pers obs) and lack of logging in its range, I doubt this species is particularly threatened.

  2. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 Red List would be to list:

    S. leucopsis and S. przewalskii as Least Concern.

    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.

Comments are closed.