Archived 2016 topics: White-winged Fantail (Rhipidura cockerelli) is being split: list R. cockerelli and R. coultasi as 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.

White-winged Fantail Rhipidura cockerelli is being split into R. cockerelli and R. coultasi, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, R. cockerelli was listed as Near Threatened under criteria A2c+3c+4c, on the basis that ‘ongoing deforestation, which is likely to be increasing in intensity, is thought to be causing it to undergo a moderately rapid population reduction’ (BirdLife International 2016). R. cockerelli (as now defined following the taxonomic change) is found in primary forest and mature secondary forest on Bougainville, Papua New Guinea, and most of the Solomon Islands (see Boles 2016). It is moderately common to common at low densities (Boles 2016). However, it prefers lowland forest and this has been extensively logged in the Solomons, and logging is predicted to increase in intensity in the future. It is intolerant of degraded forest (BirdLife International 2016) and so logging is likely to be causing a moderately rapid population decline. This population reduction has not been quantified, but may not be sufficient for listing as Vulnerable, and so further information is requested regarding possible population trends and the rate of habitat loss within this species’s range. However, in the absence of further information it is proposed that this species be listed as Near Threatened under criteria A2c+3c+4c.

R. coultasi is moderately common to common at low densities in primary and mature secondary forest on the island of Malaita in the Solomon Islands (Boles 2016). However, it prefers lowland forest and this habitat has been extensively logged in the Solomons, with logging potentially going to increase in intensity in the future. It is intolerant of degraded forest (BirdLife International 2016) and so logging is likely to be causing a moderately rapid population decline. This population reduction has not been quantified, but may not be sufficient for listing as Vulnerable. We request further information regarding possible population trends and the rate of habitat loss within this species’s range, but in the absence of further information it is proposed that this species be listed as Near Threatened under criteria A2c+3c+4c.

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

References:

BirdLife International 2016. Species factsheet: Rhipidura cockerelli. Downloaded from http://www.birdlife.org on 19/09/2016.

Boles, W. 2016. Cockerell’s Fantail (Rhipidura cockerelli). 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/59179 on 19 September 2016).

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-winged Fantail (Rhipidura cockerelli) is being split: list R. cockerelli and R. coultasi as Near Threatened?

  1. Guy Dutson says:

    cockerelli occurs at lower densities in logged forest (Buckingham et al. 1995 present some approximate densities suggesting that it is 40% less common in logged lowland forest than old-growth lowland forest). Katovai et al give an area of the extent of logging across the species’ range. NT A is perhaps over-precautionary given the slow rate of forest loss and degradation across Bougainville.

    Boles 2016 presents nothing specific for R. coultasi which is uncommon to rare. My records are: 1-2 seen at three locations on three visits 1997-2004 totalling 12 days. All were in or beside old-growth forest above 300 m. This would be consistent with VU C2aii.

  2. James Westrip (BirdLife) says:

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

    R. cockerelli as Least Concern.

    R. coultasi as Near Threatened 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.

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