Archived 2017 topics: Polynesian Imperial-pigeon (Ducula aurorae): downlist to Vulnerable?

BirdLife Species factsheet for Polynesian Imperial-pigeon: http://datazone.birdlife.org/species/factsheet/polynesian-imperial-pigeon-ducula-aurorae

 

Polynesian Imperial-pigeon, Ducula aurorae, is currently listed as Endangered under criterion D on the basis that it has been estimated to have a very small population, and probably only occurs on only one very small island (BirdLife International 2017). The species is now known only from Makatea in the Tuamotu Archipelago, French Polynesia. It has also been recorded from Tahiti and Moorea in the Society Islands, but by 1986-1990 it was restricted to the Papeno`o and Hitia`a valleys in Tahiti (Monnet et al. 1993). It was not found on Tahiti in 1998 or 2006 and so is now considered to no longer persist there (Thibault and Cibois 2006), while it likely went extinct on Moorea before 1921 (Gibbs et al. 2001).

In 1986-1987 the population on Makatea was judged to be in the range of 100-500 individuals, but following a decline in hunting on the island, the population was thought to have increased (Thibault and Guyot 1987, Thibault and Cibois 2006). A more recent survey, in 2009, estimated that the population on the island, and so the global population of this species, was 1,206 individuals (95% C. I., 867-1,677) (Albar et al. 2009, 2010). This roughly equates to 570-1,200 mature individuals, and means that the species would not meet the threshold for Endangered under criterion D (<500 mature individuals). This population information led to a BirdLife Globally Threatened Bird Forum topic regarding the status of this species (BirdLife International 2013), but the species was at the time retained as Endangered.

The recent regional assessment of the birds of France (UICN France et al. 2015), which included the birds of French Polynesia, listed the Polynesian Imperial-pigeon as Vulnerable under criteria D1+2. The population size estimate derived from Albar et al. (2009, 2010) suggests that the species does warrant listing as Vulnerable under criterion D1. Additionally, while the population on Makatea is currently stable or increasing, potential threats exist that could severely threaten the species there including phosphate mining and the possibility of the arrival of the Swamp Harrier, Circus approximans, on the island, which may have affected the species in the past (Holyoak and Thibault 1984, Thibault 1988, Seitre and Seitre 1991, Thibault and Cibois 2006, P. Raust in litt. 2013, C. Blanvillain in litt. 2013). The fact that this species is found only on one small island and there are these plausible future threats that could drive the species to CR or EX in only a short time, mean it also warrants listing as Vulnerable under criterion D2. Therefore it is suggested that this species be listed as Vulnerable under criteria D1+2 in line with its regional listing.

We welcome any comments regarding this proposed downlisting.

 

References

Albar, G.; Gouni, A.; Kesler, D.; Autai, T.; Serra, C.; Faulquier, L. 2009. Etude de l’avifaune endémique de l’île de Makatea (archipel des Tuamotu, Polynésie française). Rapport non publié. Société d’Ornithologie de Polynésie, Tahiti, Polynésie française.

Albar, G.; Dylan C. Kesler, D. C.; Gouni, A. 2010. Observations and status of birds of Makatea and Niau Islands, Tuamotu Archipelago, French Polynesia.

BirdLife International. 2013. Archived 2012-2013 topics: Polynesian Imperial-pigeon (Ducula aurorae): downlist to Vulnerable? https://globally-threatened-bird-forums.birdlife.org/2013/01/polynesian-imperial-pigeon-ducula-aurorae-downlist-to-vulnerable/. Accessed on 22/03/2017.

BirdLife International. 2017. Species factsheet: Ducula aurorae. Downloaded from http://www.birdlife.org on 22/03/2017.

Gibbs, D.; Barnes, E.; Cox, J. 2001. Pigeons and doves: a guide to the pigeons and doves of the world. Pica Press , Robertsbridge, U.K.

Holyoak, D. T.; Thibault, J.-C. 1984. Contribution à l’étude des oiseaux de Polynésie orientale. Memoires du Museum National d’Histoire Naturelle – Serie A: Zoologie 127: 1-209.

Monnet, C.; Thibault, J.; Varney, A. 1993. Stability and changes during the twentieth century in the breeding landbirds of Tahiti (Polynesia). Bird Conservation International 3: 261-280.

Seitre, R.; Seitre, J. 1991. Causes de disparition des oiseaux terrestres de Polynésie Française. South Pacific Regional Environment Programme, Nouméa.

Thibault, J.-C. 1988. Menaces et conservation des oiseaux de Polynésie Française. In: Thibault, J.-C.; Guyot, I. (ed.), Livre rouge des oiseaux menacés des régions françaises d’outre-mer, pp. 87-124. Conseil International pour la Protection des Oiseaux, Saint-Cloud.

Thibault, J.-C.; Cibois, A. 2006. Une situation favorable pour le Rupe de Makatea. Te Manu 54: 2-3.

Thibault, J.-C.; Guyot, I. 1987. Recent changes in the avifauna of Makatea Island (Tuamotus, Central Pacific). Atoll Research Bulletin 300: 1-13.

UICN France; MNHN; SOP Manu. 2015. La Liste rouge des espèces menacées en France – Chapitre Oiseaux de Polynésie française. Paris, France.

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8 Responses to Archived 2017 topics: Polynesian Imperial-pigeon (Ducula aurorae): downlist to Vulnerable?

  1. caroline Blanvillain says:

    The threat for the mining project is at a very high level at the moment. Could be better to wait the evolution of the situation before to change the states of this bird.

  2. Ghestemme Thomas says:

    Agree with the mining project threat which can reduce the habitat and bring invasive species. To my opinion, the estimation of 2009 is not so confident and the numbers may have been overestimated. Finally, a new survey is needed to compare to the 2009 data and decide then if the species can be downlisted

  3. Philippe Raust says:

    As long as the revival of mining phosphate on Makatea is still on the table, after first extraction tests in 2016, it not appropriate to downlist Ducula aurorae. Makatea is classified as IBA in danger, AZE site and is the last place in the world where D. aurorae is found.

  4. Hannah Wheatley (BirdLife) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2017 Red List would be to list Ducula aurorae as VU under criteria D1+2.

    There is now a period for further comments until the final deadline of 4 August, 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.

  5. caroline Blanvillain says:

    The species has been extirpated from its main range (Tahiti island) quite recently (extinction has occured in this island less than 30 years ago) – did this criteria is taken in consideration ?

  6. Philippe Raust says:

    I do not understand the conclusion which would be to downlist D. aurorae as vulnerable (based on available information). You received three independant comments from local practitioners which conclude NOT to change the present classification (EN).
    The local govt approved last week the mining project and it would be a very bad signal to downgrade the status of that unique endemic threatened species.

  7. James Westrip (BirdLife) says:

    Thank you for these recent comments.

    Just to confirm the decision making process at time of preliminary decisions:
    – the extirpation from Tahiti falls out of the time frame (3 generations or 10 years) used for making decisions
    – the available information at the time of making this decision was that mining was a plausible future threat that could drive the species to CR or EX in a short space of time, which combined with the potentially limited number of ‘locations’ (as defined by IUCN) fits the conditions for Vulnerable under criterion D2.

    However, given this new information provided we will be able to review our decision before final decisions to submit to IUCN are made.

  8. Hannah Wheatley (BirdLife) says:

    Recommended categorisation to be put forward to IUCN

    Following further review, the recommended categorisation for this species has been changed.

    Taking into account the new information about the plan for mining on Makatea, the high degree of certainty and the imminent nature of this plan, we can precautionarily project a future continuing decline in the area of habitat and the number of mature individuals of Ducula aurorae.

    The species is judged to have 2-5 locations*. The species therefore qualifies to be listed as Endangered under Criteria B1ab(ii,iii,v)+2ab(ii,iii,v); C2a(ii).

    Final 2017 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

    *Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

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