CR
Black-naped Pheasant-pigeon Otidiphaps insularis



Justification

Justification of Red List Category

This species is poorly-known and is known to science only from two specimens, collected in 1882. Based on reports from local people, it is believed to remain extant, but it may have a very small population. It is inferred to be declining based on a decline in the extent of its forest habitat. It is therefore classified as Critically Endangered.

Population justification

There is no estimate of the population density of any Otidiphaps sp., but a handful of calling O. nobilis have been heard calling per square kilometre in suitable hill forest at Varirata National Park (G. Dutson pers. comm. 2016). An analysis of satellite forest cover data suggested that there was 1,140 km2 of forest in the range of O. insularis in 2021 (Global Forest Watch 2021). Based on this information, the maximum population size may be estimated to number up to several thousand mature individuals. However, there have been no recent sightings of the species despite recent visits from researchers and birdwatchers (Gregg et al. 2020, J. Bergmark in litt. 2021), and surveys of the Kilkerran Massif in 2019 failed to record the species (Gregg et al. 2020), which suggests that the population size may now be extremely small. Nevertheless, local people have recently reported hunting the species and finding an active nest (Gregg et al. 2020), which suggests that the species persists in low numbers. The population size is therefore estimated to be smaller than 250 mature individuals, and is here placed in the band 50-249 mature individuals.

Given the species's small range with contiguous habitat, there is assumed to be a single subpopulation.



Trend justification
The species is inferred to be undergoing a slow decline owing to the loss of its forest habitat, which is subject to pressure for logging and conversion for subsistence agriculture. An analysis of satellite forest cover data indicated that forest was being lost in the species's range at a rate equivalent to 10% over three generations over the period of 2001-2019, with significantly higher rates seen since 2014 (Global Forest Watch 2021). Extrapolating into the future, it is suspected that 10-19% of tree cover may be lost over the next three generations. Hunting is also likely to be contributing to declines. The species's population size is therefore suspected to have undergone a reduction of 5-15% over the past three generations, and to undergo a reduction of 5-24% over the next three generations.

Distribution and population

Otidiphaps insularis is endemic to Fergusson Island (D’Entrecasteaux Islands), Papua New Guinea. It is known to science only from two specimens collected in 1882 (Godman and Salvin 1883). Although there has been little survey effort, there have been recent visits from researchers and birdwatchers (Gregg et al. 2020, J. Bergmark in litt. 2021). Surveys of the Kilkerran Massif in 2019 failed to record the species, but local people reported hunting the species and finding an active nest (Gregg et al. 2020).

Ecology

It inhabits primary rainforest, where it forages on the forest floor (del Hoyo et al. 2020). Pheasant-pigeons Otidiphaps spp prefer hilly and lower montane areas to at least 2,050 m (although they also occur in lowlands), feed on seeds and fallen fruit, and nest on the ground (del Hoyo et al. 1997, 2020, Gibbs et al. 2001). They appear to be able to tolerate some disturbance, but not hunting (J. Bergmark in litt. 2021).

Threats

Upland forest on Fergusson is relatively intact, however small-scale habitat loss occurs, particularly in the lowlands, as forest is converted for subsistence agriculture gardens, and in 2012 there was a resumption of logging, which continues throughout central and eastern parts of the island (Gregg et al. 2020). The species is hunted (Gregg et al. 2020), which may be contributing to declines. Other pheasant-pigeon species are easily hunted and seem to disappear in hunted forest (J. Bergmark in litt. 2021). Introduced predators may also pose a threat. Pigs and Polynesian Rats are established on the island (Atkinson and Atkinson 2000), and may predate on the species's eggs. Large ships frequently visit the island, and the introduction of further alien predators such as cats or Black or Norwegian Rats is a potential future threat (Gregg et al. 2020), although they may already be present (G. Dutson in litt. 2021).

Conservation actions

Conservation and research actions underway
No targeted actions are known.
 
Conservation and research actions proposed
Carry out surveys to detect individuals and to estimate the population size. Research threats to the species. Continue to monitor habitat loss.

Protect significant areas of remaining primary forest. Lobby against large-scale development of forested areas. Limit logging and mining operations through agreements with government and the private sector. Establish biosecurity protocols to limit the risk of further invasive mammals being introduced.

Identification

46 cm. A large, terrestrial pigeon with a full, laterally compressed black tail that is pumped up and down when walking. The head, underparts, rump and lower back are purplish-black, the short rounded wings and mantle chestnut. Similar spp. The other Otidiphaps do not co-occur and have either a glossy-green, grey-white or bright white hindneck. Voice. A loud. far-carrying "wu-huwoooooa" rising and falling in pitch before trailing off at the end.

Acknowledgements

Text account compilers
Wheatley, H.

Contributors
Mitchell, D., Butchart, S., North, A., Ekstrom, J., Martin, R., Taylor, J., Symes, A., Brusland, S., Davis, R.A., Dutson, G. & Bergmark, J.


Recommended citation
BirdLife International (2023) Species factsheet: Otidiphaps insularis. Downloaded from http://www.birdlife.org on 02/02/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/02/2023.