Archived 2014 discussion: White-backed Woodpecker (Dendrocopos leucotos) is being split: list D. owstoni as Endangered?

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines

Lynx Edicions and BirdLife International will soon publish 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 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), 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-backed Woodpecker Dendrocopos leucotos is being split into D. leucotos and D. owstoni, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, D. leucotos (BirdLife species factsheet) was listed as Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria. This species was estimated to have an extremely large range, and hence did not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence of less than 20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appeared to be negative, the decline was not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (at least a 30% decline over ten years or three generations). The population size is extremely large, and hence did not approach the thresholds for Vulnerable under the population size criterion (fewer than 10,000 mature individuals with a continuing decline estimated to be at least 10% over ten years or three generations, or with a specified population structure).

D. owstoni is endemic to Amami-oshima (Amami Island) in the northern Ryukyu Islands (Japan), where it is restricted to mature evergreen broadleaved hill forest (Winkler et al. 1995, del Hoyo et al. 2002). It is suggested that it qualifies as Endangered under criterion C2a(ii), on the basis that there may be fewer than 2,500 mature individuals (it has previously been estimated to number fewer than 630 pairs [Winkler et al. 1995]), forming one subpopulation, which is thought to be in decline owing to limited logging and road construction.

D. leucotos (as defined following the taxonomic change, and incorporating all other forms) occurs widely across Eurasia (del Hoyo et al. 2002) and is likely to warrant listing as Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.

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

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (2002) Handbook of the birds of the world, Vol 7: Jacamars to Woodpeckers. Barcelona, Spain: Lynx Edicions.

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.

Winkler, H., Christie, D. A. and Nurney, D. (1995) Woodpeckers: a guide to the woodpeckers, piculets and wrynecks of the world. Robertsbridge, U.K.: Pica Press.

Related posts:

  1. Archived 2010-2011 topics: Black-backed Thornbill (Ramphomicron dorsale) and Santa Marta Wren (Troglodytes monticola): uplist both to Endangered?
  2. Archived 2012-2013 topics: Black-throated Babbler (Stachyris nigricollis) and Fluffy-backed Tit-babbler (Macronous ptilosus): downlist both to Least Concern?
  3. Archived 2014 discussion: Checker-throated Woodpecker (Picus mentalis) is being split: list P. mentalis as Vulnerable and P. humii as Near Threatened?
  4. Archived 2010-2011 topics: Grey-backed Tachuri (Polystictus superciliaris): downlist to Least Concern?
  5. Archived 2012-2013 topics: Red-cockaded Woodpecker (Picoides borealis): downlist to Near Threatened?
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3 Responses to Archived 2014 discussion: White-backed Woodpecker (Dendrocopos leucotos) is being split: list D. owstoni as Endangered?

  1. Joe Taylor says:

    The following comments were received from Ken Ishida on 6 September 2013:

    The population is quite conservative on its distribution within Amami-oshima Island, some individuals transfer to Kakeroma-jima Island near Amami-oshima (1 km at the shortest) mainly out of breeding season, and we have no breeding observation at Kakeroma-jima. The population of other D. leucotos inhabits farther than 300km (Kyushu Island, abundant) and the Formosan population is the smallest. So I believe there is no chance for Amami woodpecker to hybrid with the other.

    We have nematoda infection pandemic on the endemic (< southern islands of Japan) pine trees and lots of dead large pines on Amami Islands in a recent decade, and woodpecker have been utilised the dead trees for their foraging and nesting (temporally). Kakeroma-jima is the first (early) place of this pandemic on the Islands.

  2. Joe Taylor says:

    Preliminary proposals

    Based on available information and comments posted above, our preliminary proposals for the 2014 Red List would be to treat:

    D. leucotos as Least Concern

    D. owstoni as Near Threatened under criterion D

    There is now a period for further comments until the final deadline of 31 March, after which recommended categorisations will be put forward to IUCN.

    The final Red List categories will be published on the BirdLife and IUCN websites in mid-2014, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Andy Symes says:

    Recommended categorisations to be put forward to IUCN

    Following further review, there have been no changes to our preliminary proposals for the 2014 Red List status of these species.

    The final categorisations will be published later in 2014, following further checking of information relevant to the assessments by BirdLife and IUCN.

Comments are closed.