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.
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? http://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.