Archived 2016 topics: Dull Flycatcher (Myiagra hebetior) is being split: list M. hebetior as Near Threatened or Vulnerable and M. eichhorni as Least Concern? Request for information for M. cervinicolor.

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.

Dull Flycatcher Myiagra hebetior is being split into M. hebetior, M. cervinicolor and M. eichhorni, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, M. hebetior was listed as Least Concern on the basis that it did not approach the threshold for listing as Vulnerable under any criterion. M. hebetior (as defined now following the taxonomic change) is endemic to the island of St. Matthias in the Bismarck Archipelago in native forest and forest edge, as well as possibly secondary forest (Gregory 2016). Its habitat is limited as most of the island has been logged, and it is prone to further clearance. Given the highly restricted range of this species (Extent of Occurrence: 386km2), the population is assumed to be very small, and may number fewer than 10,000 mature individuals. Therefore, it is proposed that this species be listed as Vulnerable or Near Threatened under criterion C2a(ii).

M. eichhorni is found on the islands of New Ireland, New Britain and New Hannover in native forest and forest edge (Gregory 2016). It may also occur in secondary growth, yet remains most common in mid-montane forest (Gregory 2016). The species is suspected to be in decline due to continuing habitat clearance (del Hoyo et al. 2006) as most lowland forest in the range has been logged or may be in the future. However, this is not the case at higher altitudes, and any declines are not thought severe enough to warrant listing under category A. The population is not thought to approach the threshold for Vulnerable (<10,000 mature individuals), and neither does its Extent of Occurrence (c.144,500km2) it is therefore proposed that this species be listed as Least Concern.

M. cervinicolor is endemic to forest on the island of Djaul, off the north-west coast of New Ireland, although it may tolerate forest edge and secondary growth (Gregory 2016). There is little information regarding possible threats to this species, and the population size has not been quantified, though it is suspected to be small given the restricted range of this species (Extent of Occurrence: c.165 km2). Further information is requested for this species, but given its restricted range it is possible that it may qualify as Near Threatened or Vulnerable under criterion D2 depending on the existence of plausible future threats that could cause rapid population declines.

References:

del Hoyo, J., Elliott, A. and Christie, D. 2006. Handbook of the Birds of the World, vol. 11: Old World Flycatchers to Old World Warblers. Lynx Edicions, Barcelona, Spain.

Gregory, P. 2016. Lesser Shining Flycatcher (Myiagra hebetior). 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/59265 on 15 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: Dull Flycatcher (Myiagra hebetior) is being split: list M. hebetior as Near Threatened or Vulnerable and M. eichhorni as Least Concern? Request for information for M. cervinicolor.

  1. Guy Dutson says:

    M. hebetior (as defined here) is little-known except for the recent WCS RAP (Cuthbert in Whitmore et al. 2015) which described it as less common and more restricted to old-growth forest than the (currently Near Threatened) endemic monarch and fantail. In 1997, I recorded 5 in 5 hours (1.5 hours raining) on a logging road in the hills, plus 7 in 16 hours in patchy secondary forest, unlogged patches and gardens in the lowlands. It was usually seen in shady patches of tall trees, including remnant pockets of forest within mosaics of secondary habitats. Given the likelihood of a population size <10,000 and the relatively rapid rates of logging on Mussau (Whitmore et al; Tracewski et al 2016), it could qualify as VU C2aii.

    M. eichhorni is relatively common in the hills. Current rates of forest loss (Bryan and Shearman 2015) support its listing as LC.

    M. cervinicolor is little-known. In 22 hours of intensive observations in 1997 in secondary forest of variable levels of degradation, I recorded 18 individuals. It appeared to be more common in old-growth forest including mature secondary forest, less common in secondary regrowth and regrowing gardens and extending to some extent into mangroves. (Males are easily confused with Shining Flycatcher M. alecto which is common in mangroves and widespread in secondary habitats.) The Hansen data suggest that forest loss is significant and could qualify the species as C2aii. I doubt that it would qualify under D – there are likely multiple logging concessions.

  2. James Westrip (BirdLife) says:

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

    M. eichhorni as Least Concern.

    M. hebetior and M. cervinicolor 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.

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