Archived 2014 discussion: Painted Buttonquail (Turnix varius) is being split: list T. novaecaledoniae as Critically Endangered (Possibly Extinct)?

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.

Painted Buttonquail Turnix varius is being split into T. varius and T. novaecaledoniae, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, T. varius (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 IUCN Red List criteria.

T. novaecaledoniae is endemic to New Caledonia, where it is described as rare or possibly already extinct (Madge and McGowan 2002). It is known from the type specimen in the British Museum, described by Ogilvie-Grant in 1889 and from a 1912 specimen taken by Sarasin (Warner 1947).

Fossil specimens of this taxon were collected from Mé Auré Cave by Boyer et al. (2010), who showed evidence for a sustained decline in abundance over time and regard it as extirpated. However, fossils found at shallow depths at the Pindai Caves by Anderson et al. (2010) make them more optimistic about its survival.

Although surveys and fieldwork conducted since the early 20th century have not recorded this taxon (Warner 1947, Ekstrom et al. 2002, Barré et al. 2009), these efforts are not regarded as comprehensive by Szabo et al. (2012), and they consider it most appropriately listed as Critically Endangered (Possibly Extinct). Threats include habitat clearance and degradation through agricultural intensification, urbanisation, grazing and fire, as well as the effects of hunting and introduced predators.

On the basis of available information, the species may qualify as Extinct, although optimistically it could be listed as Critically Endangered (Possibly Extinct) under criterion C2a(ii), assuming that if it is extant its population probably numbers fewer than 250 mature individuals and is likely to be in on-going decline owing to continued threats. Further information is required.

T. varius (as defined following the taxonomic change and incorporating scintillans) is widespread in Australia and Tasmania, and present on islands off the western coast of Australia (Houtman Abrolhos, North Island, East Wallabi Island, West Wallabi Island and Seagull Island) (Madge and McGowan 2002, Garnett et al. 2010). It is described as uncommon to locally common, but probably declining in the south of its range, particularly in Tasmania, where it is now very rare (Madge and McGowan 2002). Despite these declines, it is thought likely to be listed as Least Concern (see Garnett et al. 2011), on the basis that it does not approach the thresholds for Vulnerable under any of the IUCN Red List criteria.

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

References:

Anderson, A., Sand, C., Petchey, F. and Worthy, T. H. (2010) Faunal extinction and human habitation in New Caledonia: Initial results and implications of new research at the Pindai Caves. Journal of Pacific Archaeology 1: 89–109.

Barré, N., Herbert, O., Aublin, R., Spaggiari, J., Chartendrault, V., Baillon, N. and Le Bouteiller, A. (2009) Troisième complement à la liste de oiseaux de Nouvelle-Calédonie. Alauda 77: 287-302.

Boyer, A. G., James, H. F., Olson, S. L. and Grant-Mackie, J. A. (2010) Long-term ecological change in a conservation hotspot: the fossil avifauna of Mé Auré Cave, New Caledonia. Biodiversity Conservation 19: 3207–3224.

del Hoyo, J., Elliott, A. and Sargatal, J. (1996) Handbook of the birds of the world, Vol 3: Hoatzin to Auks. Barcelona, Spain: Lynx Edicions.

Garnett, S. T., Szabo, J. K. and Dutson, G. (2011) The action plan for Australian birds 2010. Collingwood, Australia: CSIRO Publishing.

Madge, S. and McGowan, P. (2002) Pheasants, partridges and grouse: including buttonquails, sandgrouse and allies. London, UK: Christopher Helm (Helm Identification Guide).

Szabo, J. K., Khwaja, N., Garnett, S. T., Butchart, S. H. M. (2012) Global Patterns and Drivers of Avian Extinctions at the Species and Subspecies Level. PLoS ONE 7(10): e47080. doi:10.1371/journal.pone.0047080

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.

Warner, D. W. (1947) The ornithology of New Caledonia and the Loyalty Islands. PhD Thesis. Ithaca, NY: Cornell University.

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3 Responses to Archived 2014 discussion: Painted Buttonquail (Turnix varius) is being split: list T. novaecaledoniae as Critically Endangered (Possibly Extinct)?

  1. Joe Taylor says:

    Further to the posting of this discussion topic, please note the IUCN guidelines for defining Possibly Extinct taxa:

    “Critically Endangered (Possibly Extinct) taxa are those that are, on the balance of evidence, likely to be extinct, but for which there is a small chance that they may be extant. Hence they should not be listed as Extinct until adequate surveys have failed to record the species and local or unconfirmed reports have been investigated and discounted. ‘Possibly Extinct in the Wild’ correspondingly applies to such species known to survive in captivity.

    Note that ‘Possibly Extinct’ is a tag, and not a new Red List Category.

    Different standards of evidence are required from assessors when deciding to assign a taxon to the Extinct or Critically Endangered (Possibly Extinct) categories. Assignment to the Extinct category requires evidence beyond reasonable doubt that the last individual of the taxon has died. Assignment of the ‘Possibly Extinct’ tag requires that on the balance of evidence, the taxon is likely to be extinct, but there is a small chance that it may be extant. Relevant types of evidence supporting a listing of extinction include (Butchart et al. 2006):
    • For species with recent last records, the decline has been well documented.
    • Severe threatening processes are known to have occurred (e.g., extensive habitat loss, the spread of alien invasive predators, intensive hunting, etc.).
    • The species possesses attributes known to predispose taxa to extinction, e.g. flightlessness (for birds)
    • Recent surveys have been apparently adequate and appropriate to the species’ detectability, but have failed to detect the species.

    Such evidence should be balanced against the following considerations (Butchart et al. 2006):
    • Recent field work has been inadequate (any surveys have been insufficiently intensive/extensive, or inappropriately timed; or the species’ range is inaccessible, remote, unsafe or inadequately known).
    • The species is difficult to detect (it is cryptic, inconspicuous, nocturnal, nomadic, silent or its vocalisations are unknown, identification is difficult, or the species occurs at low densities).
    • There have been reasonably convincing recent local reports or unconfirmed sightings.
    • Suitable habitat (free of introduced predators and pathogens if relevant) remains within the species’ known range, and/or allospecies or congeners may survive despite similar threatening processes.

    Similar considerations apply when assigning a taxon to either the Extinct in the Wild or Critically Endangered (Possibly Extinct in the Wild) categories.”

    Reference:

    IUCN Standards and Petitions Subcommittee (2013) Guidelines for Using the IUCN Red List Categories and Criteria. Version 10.1. Prepared by the Standards and Petitions Subcommittee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

  2. Joe Taylor says:

    Preliminary proposals

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

    T. varius as Least Concern

    T. novaecaledoniae as Critically Endangered (Possibly Extinct) 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.