Archived 2014 discussion: Checker-throated Woodpecker (Picus mentalis) is being split: list P. mentalis as Vulnerable and P. humii as Near Threatened?

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.

Checker-throated Woodpecker Picus mentalis is being split into P. mentalis and P. humii, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, P. mentalis (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 decreasing, 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 has not been quantified, but it was not believed to 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).

The pre-split species is characterised as preferring primary forest, but also occurring in some disturbed habitats, from the lowlands to lower montane areas (Winkler et al. 1995, del Hoyo et al. 2002).

P. mentalis (as defined following the taxonomic change) is endemic to Java (Winkler et al. 1995, del Hoyo et al. 2002).  The species could qualify as Vulnerable under criteria A2c+3c+4c, as it may be in rapid population decline (30-49% over three generations [c.17 years]), owing to on-going declines in the area and quality of suitable habitats.

P. humii occurs in the Thai-Malay Peninsula, Sumatra and Borneo (Winkler et al. 1995). It may qualify as Near Threatened under criteria A2c+3c+4c, if it is thought to be undergoing a moderately rapid population decline (approaching 30% over three generations [c.17 years]), owing to on-going habitat loss and degradation.

Comments on these suggested categories are invited 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 2014 discussion: Great Lizard-cuckoo (Coccyzus merlini) is being split: list C. bahamensis as Near Threatened?
  2. Archived 2011-2012 topics: Blue-moustached Bee-eater (Merops mentalis): request for information
  3. Archived 2010-2011 topics: Pale-throated Wren-babbler (Spelaeornis kinneari): uplist to Vulnerable?
  4. Archived 2012-2013 topics: Black-throated Blue Robin (Luscinia obscura ): downlist to Near Threatened?
  5. Archived 2010-2011 topics: White-throated Wren-babbler (Rimator pasquieri): uplist to Endangered?
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4 Responses to Archived 2014 discussion: Checker-throated Woodpecker (Picus mentalis) is being split: list P. mentalis as Vulnerable and P. humii as Near Threatened?

  1. Martjan Lammertink says:

    Regarding Picus mentalis on Java, I do not believe that the ongoing rate of forest loss on Java is as rapid as to cause a population decline of 30-49% in c. 17 years in this species. Historical forest loss rates on Java were very high and the island maintains less than 10% of its area as closed canopy forest. However, much of the now remaining forest is protected. The recent work by Hansen et al. (2013) on global forest change shows rapid forest loss in parts of Indonesia as Sumatra and Kalimantan, but a nearly stable situation on Java during 2000-2012 (http://www.earthenginepartners.appspot.com/science-2013-global-forest). There is no reason either to assume rapid forest loss in Java in coming decades. Picus mentalis is not exceedingly rare on Java: Van Balen (1999) recorded it in 3 out of 19 forest fragments, and eBird.org has 3 records of it, from 1987, 2011, and 2013. The most appropriate category for Picus mentalis seems to be Least Concern.

    Regarding Picus humii, on Borneo Lammertink (2004) found a 85% density decline in a gradient of sites from primary to selectively, commercially logged lowland forests. A review of studies of logging impact on birds in lowland forests found Picus humii to decline in 3 out of 5 studies (Meijaard et al. 2005). However Picus hummi occurs in moderate densities in hill forest of which much remains and where large populations of this species persist. Of the 10 lowland forest woodpecker species endemic to the Sundaic region, Picus hummi is probably in the most rapid decline, and Near-Threatened is an appropriate category to mark that distinction.

    References:

    Balen, S. van. 1999. Birds on fragmented islands: persistence in the forests of Java and Bali. PhD thesis, Universiteit Wageningen.

    Lammertink, M. 2004. A multiple-site comparison of woodpecker communities in Bornean lowland and hill forests. Conservation Biology 18:746-757.

    Meijaard, E., Sheil, D., Nasi, R., Augeri, D., Rosenbaum, B., Iskandar, D., Setyawati, T., Lammertink, M., Rachmatika, I., Wong, A., Soehartono, T., Stanley, S. and O’Brien, T. 2005. Life after logging: reconciling wildlife conservation and production forestry in Indonesian Borneo. Centre for International Forestry (CIFOR) and United Nations Educational, Scientific and Cultural Organization (UNESCO), Bogor, Indonesia. 345pp.

  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:

    P. mentalis as Least Concern

    P. humii as Near Threatened under criteria A2c+3c+4c

    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. Martjan Lammertink says:

    Although I recommended Least Concern for the Javan endemic Picus mentalis, I now have second thoughts and recommend Near-Threatened for this species, for the following reasons. Although Picus humii is in more rapid decline than mentalis, the current global population of humii is still far larger than that of mentalis. P. mentalis is now largely restricted to mountain forest fragments, a situation where P. hummi may end up in several decades if all (secondary) lowland forests in the range of hummi were cleared. It would thus be an odd discrepancy to have mentalis as Least Concern and hummi as Near Threatened. It is better to have both listed as Near Threatened, albeit for different reasons: a rather rapid decline in humii, and a small and fragmented global population in mentalis. As I wrote earlier, P. mentalis seems not exceedingly rare but neither is it very common, with 3 records in eBird, compared to 15 records of Javan Trogon (Harpactes reinwardtii) in eBird. I do stand by my earlier assessment that Vulnerable is too high a threat category for mentalis because it does not suffer from habitat loss at a rate that would make it qualify for that category.

  4. Andy Symes says:

    Recommended categorisations to be put forward to IUCN

    Based on available information and comments posted above, our recommended categorisations to be put forward to IUCN for the 2014 Red List are:

    P. mentalis as Near Threatened, nearly meeting the thresholds for Vulnerable under criterion C2a(i) – change to the preliminary proposal

    P. humii as Near Threatened, nearly meeting the thresholds for Vulnerable under criteria A2c+3c+4c

    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.

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