Hottentot Buttonquail (Turnix hottentottus): Revise global status?

Birdlife International factsheet for Hottentot Buttonquail

Hottentot Buttonquail is endemic to South Africa, and inhabits montane and lowland fynbos and coastal strandveld habitats (Debus & Kirwan, 2020). It was previously thought to have a small population size of 250-999 mature individuals (Birdlife International, 2020), but recent studies suggest the population may actually be much higher (Lee et al., 2018a; Lee et al., 2018b).

The main threat known to this species is the degradation of habitat by invasive alien species, agricultural pressures, and climate change (Lee et al., 2018b). Hottentot Buttonquail has been considered Endangered under the Criterion C2a(i), however this may no longer be tenable in light of new information. We have therefore reassessed this species here against all the criteria.

Criterion A: The population of Hottentot Buttonquail is suspected to be declining due to ongoing habitat degradation. However, there is no quantified estimate of the rate of reduction in either mature individuals over ten years (one generation length being 3.0 years; Bird et al. 2020)*, or (to the best of our knowledge) habitat quality. This species therefore cannot be assessed against criterion A.

Criterion B: The Extent of Occurrence (EOO) for this species is far greater than the 20,000 km2 threshold needed to trigger a threatened status under Criterion B1. Under IUCN guidelines, it is the EOO not the Extent of Suitable Habitat (ESH) that is used to assess a species against this criterion (IUCN Standards and Petitions Committee, 2019). Consequently, classifying this species as Vulnerable under criterion B1 based on the lower estimates of a 10, 377 – 41, 303 km² ESH as suggested in Lee et al. (2018a) is not appropriate. Hottentot Buttonquail may therefore be considered Least Concern under Criterion B.

Criterion C: Based on a population density of 0.032 individuals/ha, and an estimated ESH of 10, 377 – 41, 303 km², the most recent population estimates for this species is 33,206 – 132,169 individuals (Lee et al. 2018a), roughly equating to a population size of 22,248 – 88,553 mature individuals. Even assuming the true population size is towards the lower end of the estimate, this is high above the <10,000 mature individuals threshold required for classification as threatened under this criterion. Hottentot Buttonquail may therefore be considered Least Concern under this criterion.

Criterion D: The new population size estimates are way above the threshold (<1000 mature individuals) for classification as threatened under Criterion D. This species may therefore be considered Least Concern under this criterion.

Criterion E: To the best of our knowledge, no quantitative analysis has been carried out for this species, so Hottentot Buttonquail cannot be assessed against this criterion.

We therefore suggest that Hottentot Buttonquail be listed as Least Concern. We welcome any comments to the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’ Red List status. Therefore, please make sure your comments are relevant to the species’ Red List status and the information requested. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International (2020) Species factsheet: Turnix hottentottus. Downloaded from http://www.birdlife.org on 27/04/2020.

Debus, S. & Kirwan, G.M. (2020). Hottentot Buttonquail (Turnix hottentottus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53536 on 27 April 2020).

IUCN Standards and Petitions Committee, 2019. Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf

Lee. A.T.K., Wright, D.R., and Wright, D.R., 2018a, Hottentot Buttonquail Turnix hottentottus: Endangered or just overlooked? Bird Conservation International, 29(1), pp. 136 – 143.

Lee. A.T.K., Wright, D.R., Wright, D.R., (2018b) Habitat variables associated with encounters of Hottentot Buttonquail Turnix hottentottus during flush surveys acrossn the Fynbos biome, Ostrich, 89:1, 13-18, DOI: 10.2989/00306525.2017.1343209

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6 Responses to Hottentot Buttonquail (Turnix hottentottus): Revise global status?

  1. Alan Lee says:

    While the species is undoubtedly more common than previously thought, it is still not that common given the size of the range (that is a small population size for such a big area). Furthermore, our early results show it is absent from transformed landscape: and 37% of the suitably modelled range is transformed (by agriculture mostly, but also alien vegetation invasions, which are increasingly turning more of the habitat here to unsuitable): the declines are certain but obviously unquantifiable. What can I say: I don’t work by these thresholds, but dropping a species initially listed as Endangered to Least Concern seems a bit excessive given the clear threats to the integrity of the biome: especially its preferred habitat (especially the Agulhas Plains). While you may not take our published suggestion of ‘Vulnerable’ – ‘Near Threatened’ seems at least to acknowledge the precarious state of the biome due to a multitude of threats (climate change, rampant alien vegetation, landscape transformation) and its endemic birds. The only species we’ve been able to invest a lot of time studying (Cape Rockjumper) is clearly vulnerable to multiple barbs from climate change.

  2. Dale Wright says:

    As a collaborator on the research project which attempted to update the population status of this species I would caution against a full down listing to Least Concern. This species is lacking primary information regarding ecology and life history and to date has been the subject of little research. Whilst our population estimates might not reach the relevant thresholds the species is doubtless under threat from both habitat loss and habitat fragmentation throughout its distribution. Our study did find very specific and dynamic habitat requirements, linked to fire regimes and vegetation age in the Fynbos Biome. The high degree of habitat fragmentation, increasing fire frequencies in the Biome and uncertainties regarding the species dispersal ability raise further concerns for its conservation. As there is no way of accurately quantifying the species decline we cannot estimate historical population sizes, nor the proportional decline to this point, however, large scale loss of habitat across its range suggests that it has been experiencing declines and will continue to do so. Whilst the species may not meet the thresholds for Vulnerable it should at least be considered Near Threatened, due to the paucity of information, very specific and dynamic habitat requirements and narrow range within South Africa. This is in line with the precautionary approach which we adopted when providing a recommendation of Vulnerable status for the species. A recommendation is to classify this species as Near Threatened, pending further research.

  3. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  4. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information, our preliminary proposal for the 2020 Red List would be to list Hottentot Buttonquail as Near Threatened under Criterion A2ce+3ce+4ce.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN. The final publication date will be publicised by IUCN here: https://www.iucnredlist.org/assessment/updates

  5. Robin says:

    As part of the Conservation Modelling project at BirdLife South Africa, our results indicate that as Alan Lee pointed out, close to 40% of the species range has already been irreversibly altered. Habitat loss is additionally further compounded by potential impacts of fragmentation. Furthermore, climate change modelling results indicate that much of the currently suitable habitat could change signifcantly in the next 20 years. Given current land-use, we calculated an EOO of ca. 11 000 km2, together with an expected AOO of less than 2000km2. Given the past and current habitat loss across the Biome, together with results suggesting impacts from climate change in the next 2 decades, we would like to propose that the species be listed as Vulnerable under criteria B1(a&b)+B2(a&b) [past and continued decline in EOO and AOO – habitat loss together with fragmentation], as well as A2ce+3ce+4ce.

  6. Red List Team (BirdLife International) says:

    Recommended categorisations to be put forward to IUCN

    Based on available information, our proposal for the 2020 Red List is to pend the decision on this species, awaiting further details and information on climate and land-use change models. The discussion for Hottentot Buttonquail will be kept open until 2021, while the current Red List category will remain unchanged in the 2020 update.

    Final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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