Archived 2014 discussion: Woolly-necked Stork (Ciconia episcopus) is being split: list C. episcopus as Vulnerable?

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.

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.


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.

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16 Responses to Archived 2014 discussion: Woolly-necked Stork (Ciconia episcopus) is being split: list C. episcopus as Vulnerable?

  1. Tom Gray says:

    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.

  2. Simon Mahood says:

    Yes, the parallel with Lesser Adjutant makes sense, it should have the same listing as that species.

  3. 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?

  4. Hugo Rainey says:

    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?

  5. R. J. Timmins says:

    In Cambodia as suggested it has a similar status to L Adjutant and population size is likely to be very similar. The main differences with the adjutant are as suggested in nesting; it does not seem to form easily targeted (for hunting) colonies, but conversely this means there are few if any protected nests, and there is not a large Tonle Sap population, hence a potentially larger proportion of the population is threatened. Nests of the species are certainly collected and the huge trees that once provided a modicum of inherant protection are rapidly disappearing, while the inherant protection of truely vast swaths of lowland forest not bisected by major roads is disappearing probably even faster. Looking for evidence of decline is not easy; most information comes from the best sites, and even in these because the information is from different observers over time I suspect large declines (e.g. 50%) could relatively easily go undetected. My guess would be that the species meets at least the threshold for EN in Cambodia. It might well do okay in a syntropic environment, but the forest area they use at present will first undergo a transition to ‘frontier’ rural country where the largely ungoverned ‘free for all’ does the damage. Looking around only the hardiest species make it through this transitionary period.

    I can’t speak for Myanmar personally, but everything I hear suggests it’s on a trajectory much more akin to other countries in SEAsia than it is the South Asia. I also wander about South Asia, having been involved in the Red Listing of several mammal species where on detailed examination their status in the subcontinent was obviously no where near as rosy as general consensus initially led one to believe. It is trends in the general landscape, rather than those in premier protected national parks that is important.

  6. Arne Jensen says:

    In the Philippines the species appears to have become extirpated or near-extirpated from Luzon. Last record in 1988 by T. Fisher from Maconacon, Isabela and one possible record from Ilocos Norte in 2004 by Kathy MacKinnon and Dr. Perry Ong. Recent reliable records are only from eastern Mindanao and of shot individuals, e.g. PICOP, Bislig, Surigao del Sur. Appears last to have been recorded in Ligawasan Marsh in 1991 (Municipality: Salipada K. Pendatun, Maguindanao) with another record of a caged individual around 2006. Whatever remains of its key habitat is rapidly being destroyed and in a national Philippine setting it could be considered critically endangered. The species surely deserves listing

  7. Frederic Goes says:

    Not much to add to above expert comments, although I would not be that alarmist about the probabibity of extinction, hence the category, at least for the Cambodian population. The species has declined, is and will continue to do so, but tricky is to quantify the extent of decline both historically and predictably.

    STATUS: A fairly common and widespread resident in forest wetlands and grasslands
    in lowlands and lower hills, both inland and along the coast. The second most
    common large waterbird in forested landscape, encountered at pools, rivers and streams, reservoirs, wet meadows, marshes within semi-evergreen and dry deciduous forests. Also frequents mangroves but usually avoids the Tonle Sap swamp forest (though single pair nesting at Prek Toal). Present throughout the forested regions, where most common in the north and northeast. Historically common in the Mekong – Tonle Sap floodplain, where now only a regular visitor to the floodplain grasslands and extirpated from the southeast. Usually in pairs or small parties, with the largest flock holding 40 birds.

    CONSERVATION: Populations have collapsed in Laos and it is extirpated from most of Thailand (Thewlis et al. 1998).The lowland forests of north and northeast Cambodia now support the largest regional population (Timmins 2008). In Cambodia, the species was historically considered the commonest stork, and seen everywhere in rice fields and close to waterholes, even near villages and roads (Delacour & Jabouille 1925b, Delacour 1929). This is no longer the case, undoubtedly reflecting a historical decline although the scale of this is difficult to determine. The floodplain population, formerly abundant, is virtually extirpated, indicating at least a major local decline probably due to habitat loss coupled with persecution. The species remains nevertheless widely distributed across the forested landscape of the country with a relatively large population. An aerial survey across northern Cambodia recorded a total of 180 birds in September 2001 i.e. about half the number of Lesser Adjutants (Barzen 2004). During this wet season peak, the species is thought to disperse throughout the landscape instead of gathering around wetlands, and so numbers detected would be a small fraction of the total sub-population. Cambodia arguably supports many thousands of birds, perhaps over 10,000, although no density data is available to support reliable population estimates. The species is probably persecuted, although as a non-colonial wet season breeder scattered over large areas, it is less likely to be seriously affected by nest harvesting. It is nevertheless experiencing a moderate decline due to the increasing loss and fragmentation of habitats throughout the country and is therefore considered nationally Near-Threatened and requires regular monitoring.

  8. Praveen J says:

    South Indian population of Woolly-necked Storks seem to be stable with no reported declines in any of the states. Though it is not as numerous as Asian Openbill or Painted Storks, it was never perhaps as numerous in the past also.
    Drawing parallels with Lesser Adjutant, which has a very restricted distribution in south India with few known sites and very few in numbers, situation of Woolly-necked Storks is not the case with flocks ranging from 30-60 birds are also noted in drying reservoir beds. I feel the south Indian population would still classify only as Least Concern. Opinions from rest of India would be welcome.

  9. 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:

    C. episcopus as Vulnerable under criteria A2cd+3cd+4cd

    C. microscelis as Least Concern

    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.

  10. Hugo Rainey says:

    More evidence from South Asia is needed to prove that across its global range this species has declined by >30% in three generations. The situation in SE Asia indicates the population is not increasing, but there is little evidence so far for a large decline (see Fred Goes’s comments above), nor is this backed by any South Asian data. Soliciting additional information from this region before suggesting any change seems sensible.

  11. Joe Taylor says:

    The following comments were received from Hem Baral and Carol Inskipp on 6 March 2014:

    Woolly-necked Stork Ciconia episcopus
    This species has recently been assessed for the national Nepal bird Red Data Book as Least Concern. It is a fairly common resident. The species has been recorded in a number of protected areas and quite widely outside the protected areas’ system. It is threatened by habitat loss and degradation, hunting, disturbance and possibly the use of agro-chemicals Its population is considered to be declining, although not to the extent that warrants a threat category.

  12. Praveen J says:

    A peek at South Asia distribution of this species in the last ten years can be seen here.

    eBird does not the most reliable data as observations from observers of varying competency level will be present. However data for a diagnostic species like Woolly-necked Stork is unlikely to have that issue in a big way.

    The species is wide-spread, no-where abundant but present in small numbers all through the range. This can be compared with Lesser Adjutant, another easy to detect species where the threat levels are compared.

    Hence, in South Asia – I doubt whether it meets any of the red list criteria.

  13. P.O. Nameer says:

    Please see the data (collected as part of the Asian Waterbird Census) on the Woolly-necked Stork for Kerala, S India between 2008 and 2014.

    36 (2008), 53 (2009), 3 (2010) 5 (2011) 19 (2012) 71 (2013) and 193 (2014). There is an increase in the count of the Woolly-necked Stork in 2014, compared to the previous years. However, this may not be because of the actual increase in the population of the Woolly-necked Storks in Kerala, but is primarily due to the fact that in 2014, the Waterbird Count in Kerala, was more comprehensive. When between 2008 and 2013 only less than 15 wetlands across the State was covered as part of the AWC, in 2014 we covered 114 sites across the State!.

    Woolly-necked Stork, in other words has never been a common/abundant stork as far as Kerala is concerned..

  14. S. Subramanya says:

    The Woolly-necked Stork (Ciconia episcopus) was never common in Karnataka, India. Mainly seen along the drying margins of lakes and in rice-fallows and always seen in small numbers and more solitary than gregarious. The situation more or less continues to be so, with no apparent change in its status in the state. Thus, I would be too reluctant to fit into any of the red list categories, right now.

  15. S. Subramanya says:

    Oops! I just wanted to say…”Thus, I would be too reluctant to fit it into any of the red list categories, right now”.

  16. 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.

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