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 2013 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.
Woolly-necked Stork Ciconia episcopus is being split into C. episcopus and C. microscelis, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, C. episcopus (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 may be moderately small to large, 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).
C. episcopus (as defined following the taxonomic change, and incorporating neglecta) occurs patchily across South Asia and South-East Asia, where it inhabits a wide range of predominantly wetland habitats, including some modified and artificial habitats (del Hoyo et al. 1992). It may qualify as Vulnerable under criteria A2cd+3cd+4cd, on the basis that it could be undergoing a rapid population decline (30-49% over three generations [c.48 years]) owing to habitat fragmentation (del Hoyo et al. 1992), as well as habitat degradation and the likely threat of widespread persecution.
C. microscelis occurs widely across sub-Saharan Africa (del Hoyo et al. 1992). It is thought 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., Elliot, A. and Sargatal, J. (1992) Handbook of the birds of the world, vol 1: Ostrich to Ducks. 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.
Related posts:
- Red-necked Falcon (Falco chicquera) is being split: list F. chicquera as Near Threatened?
- Scaly Kingfisher (Actenoides princeps) is being split: list A. regalis as Vulnerable and A. princeps as Near Threatened?
- Rainbow Lorikeet (Trichoglossus haematodus) is being split: list T. rosenbergii as Vulnerable and both T. weberi and T. forsteni as Near Threatened?
- Crestless Fireback (Lophura erythopthalma) is being split: list both L. erythopthalma and L. pyronota as Vulnerable?
- Philippine Scops-owl (Otus megalotis) is being split: list O. nigrorum as Vulnerable and O. megalotis and O. everetti as Near Threatened?
I would support the listing of Asian wooly-necked stork as Vulnerable. It is probably more widespread over a greater variety of habitats in eastern Cambodia than lesser adjutant (though less frequently observed in pure deciduous dipterocarp forest). Threats are similar to lesser adjutant in the landscape and a similar listing as Vulnerable would appear sensible.
Yes, the parallel with Lesser Adjutant makes sense, it should have the same listing as that species.
I agree with Simon and Tom that the same reasoning as for Lesser Adjutant should guide this one’s Red Listing; it has the same long-time assessment window for decline-based criteria. As indicated under the adjutant given the pace of change in SE Asia I wonder whether VU is correct; EN should certainly be considered. Although some large waterbirds like Painted Stork and Asian Openbill are increasing rapidly given the lowering motivation of people in SE Asia to kill large birds when they come across them, these are syanthropic species both nesting and feeding. As far as I am aware this is not so for Woolly-necked Stork and Lesser Adjutant, and while hunting pressures might reasonably be expected to ameliorate somewhat in the next decades in the SE Asian parts of their range, it is the habitat prognosis that is very grim. Or, do they just seem in Lao PDR and surroundings to be species of remote areas of largely natural habitat because all the ones that could live in agricultural landscapes were long ago shot and nest-robbed?
Although C. episcopus is likely to be at threat from habitat loss. It is not threatened at breeding sites in the same way as the Lesser Adjutant in SE Asia. It breeds successfully along rivers which are used by people and it does not require protection at nests to the same degree. I would recommend looking carefully at the threats across its range in Asia. In South Asia, is it as threatened as in SE Asia? Will its population really decline by >10% across the whole of this range or is it just in SE Asia?