Archived 2014 discussion: Sunda Teal (Anas gibberifrons) is being split: list A. albogularis 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.

Sunda Teal Anas gibberifrons is being split into A. gibberifrons and A. albogularis, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, A. gibberifrons (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.

A. albogularis is endemic to Andaman Islands and Great Coco Island, where it inhabits freshwater streams, ponds and lagoons, paddy-fields, freshwater and brackish swamps, tidal creeks and estuaries (Kear 2005, Rahmani and Islam 2008). It is nomadic and alights on the sea, as well as being present on many islands (Rahmani and Islam 2008). It has been noted that human disturbance to the species’s habitat, through activities such as irrigation, fishing and hunting, is considerable (Rahmani and Islam 2008). Very little of its habitat is protected, and historically the largest flocks have been recorded in the least disturbed areas. Despite the threat of disturbance, and past declines, numbers on the Andaman Islands appear to be stable or increasing, with 69-582 individuals counted in 1995-1998, and 674 individuals counted in 2003-2004 (Vijayan et al. 2006).

With recent survey data in mind, the species is estimated to have a total population of 500-1,000 individuals (Wetlands International 2006, Rahmani 2012), which is said to be increasing (Rahmani 2012). It is on this basis that the recommendation of Rahmani (2012) is followed and it is suggested that the species qualifies as Vulnerable under criterion D, because its population probably includes fewer than 1,000 mature individuals and is not thought to be in decline.

A. gibberifrons (as defined following the taxonomic change) 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:

Kear, J. (2005) Ducks, geese and swans volume 2: species accounts (Cairina to Mergus). Oxford, UK: Oxford University Press (Bird families of the world 16).

Rahmani, A. R. (2012) Threatened Birds of India – Their Conservation Requirements. Indian Bird Conservation Network: Bombay Natural History Society, Royal Society for the Protection of Birds and BirdLife International. Oxford, UK: Oxford University Press.

Rahmani, A. R. and Islam, M. Z. (2008) Ducks, geese and swans of India: Their status and distribution. Indian Bird Conervation Network: Bombay Natural History Society, Royal Society for the Protection of Birds and BirdLife International. Oxford, UK: Oxford University Press.

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.

Vijayan, L., Murugan, V. and Raja Mamannan, M. A. (2006) Conservation of Andaman Teal. TWSG News 15: 55-59.

Wetlands International (2006) Waterbird population estimates. Fourth edition. Wageningen, The Netherlands: Wetlands International.

Related posts:

  1. Archived 2010-2011 topics: Baikal Teal (Anas formosa): request for information
  2. Archived 2010-2011 topics: Campbell Islands Teal (Anas nesiotis): downlist to Endangered?
  3. Archived 2014 discussion: Greater Flameback (Chrysocolaptes lucidus) is being split: list C. strictus as Vulnerable and C. xanthocephalus as Near Threatened?
  4. Archived 2014 discussion: Mountain Imperial-pigeon (Ducula badia) is being split: list D. cuprea as Near Threatened?
  5. Archived 2014 discussion: New Zealand Pigeon (Hemiphaga novaeseelandiae) is being split: list H. chathamensis as Vulnerable and H. novaeseelandiae as Near Threatened?
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8 Responses to Archived 2014 discussion: Sunda Teal (Anas gibberifrons) is being split: list A. albogularis as Vulnerable?

  1. Glyn Young says:

    I tried to get updates on these two taxa some years back. Certainly at the time there was very little information on gibberifrons and what there was didn’t sound good. My then contacts seemed to know it best from bird markets! Sadly, confusion with gracilis to the east and lack of interest from visiting birders, who didn’t think that they could tick it and, therefore, didn’t report it hampered any assessment. Ideally separation from gracilis should have increased reporting so that there are now better ideas on numbers and threats. I think that any mangrove tree-hole nester in this region is likely to be under increasing threat. I would be wary of considering as only Least Concern.

    albogularis is not widely reported either and former surveys found very few. Again, numbers occur in poorly visited sites so assessment is very difficult. It is rarer than bernieri and I wonder if it might even qualify as Data Defficient.

    • Joe Taylor says:

      BirdLife International estimates the three-generation trend period for A. gibberifrons to be c.20 years. If threats to the species are suspected to be driving a decline approaching 30% over this time frame, the species could qualify as Near Threatened under criterion A.

  2. We were on South Andaman in March 2012, and we saw albogularis at two different locations. At Sippighat we had a sighting of five individuals, and then a flock of nearly 200 at Ogra Branj, in a small brackish waterbody. They outnumbered even the Common moorhen here. We’d be happy to send you some photos if you like.

  3. David Bishop says:

    On 21 Feb. 2013 I observed flocks totalling 400-500 at Ograbraj. This observation is in keeping with all my visits to the Andaman Islands since the tsunami.

  4. Praveen J says:

    When there is mounting evidence that Andaman Teal is on the rise, particularly in the tsunami hit wetlands of S. Andamans, would this be considered Vulnerable still under criteria D ? Ograbraj hosted a few hundred teals and another tsunami-formed wetland (Kadakkachang) had 93 nos in March 2012. A resurvey of the population is likely to come up with a count more than 1000; perhaps this is something which can be easily done by one of the researchers visiting Andamans ?

  5. 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:

    A. gibberifrons as Near Threatened under criteria A2cd+3cd+4cd

    A. albogularis as Vulnerable 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.

  6. Praveen J says:

    I had a talk with Vikram Sheel, one of the few resident bird guides in Andman Is about A. albogularis. Four days back, he saw 400-500 birds in one of the regular haunts on a birding trip with visiting bird-watchers. However, he says that – if a proper count is taken in S. Andaman (SippyGhat, Ograbraj , Kadakkachang etc), its number would surpass 1000. I believe the bird is not restricted to S. Andaman and hence there would be other population elsewhere too – some sites visited during an old survey here can be found in Vijayan, L. et al. (2006), available online.

    It seem highly likely that “Vulnerable” decision will be challenged if we go only by Criterion D. There is some evidence that the population may be fluctuating – in real or due to movements.
    http://www.indianbirds.in/pdfs/IB.5.4_103-107.pdf

    Perhaps there are other criteria to be evaluated to see if it qualifies as Vulnerable ?
    May be B1ac, B2ac, C2b ?

  7. 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.

    Note that whilst the total count of A. albogularis may surpass 1,000, it is possible that the number of mature individuals (the figure that should be assessed against the IUCN criteria) may be less than this.

    The fluctuating numbers of albogularis reported on waterfowl counts are probably not sufficient to list the species against any of the subcriteria requiring extreme fluctuations.

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