EN
Rapa Fruit-dove Ptilinopus huttoni



Justification

Justification of Red List Category
This species is classified as Endangered because the population is very small (<250 mature individuals) and confined to undisturbed forest fragments on one tiny island. However, at present the population appears to be stable.

Population justification
A population estimate of 270-274 individuals is taken from figures published in Thibault and Varney (1991).

Trend justification
The species's population is still thought to be stable (P. Raust and J. Millett in litt. 2007). However it is likely that the area of suitable habitat decreased during the 20th century and overgrazing by goats and cattle has taken place (SPREP 2001). The species is now reportedly seen more frequently, and in habitats where it was previously absent (P. Raust in litt. 2015). The invasion of P. cattleianum may have provided the species with an additional food source (P. Raust in litt. 2015). New surveys are required to quantify the population trend direction and magnitude.

Distribution and population

This species is endemic to the tiny island of Rapa in the Tubuai Islands, French Polynesia, where its population was estimated at 274 individuals (175-368) in 1989-1990 (Thibault and Varney 1991). Although it is probable that the area of available habitat has diminished during the 20th century and this may have caused a decrease in population, in 1991 there was thought to have been no serious decline since 1974 (Thibault and Varney 1991). The situation now is thought to be much the same (J. Millet in litt. 2007), but the introduction of the Chinese guava Psidium cattleianum may have provided an additional food source and be causing the population to increase, although surveys are needed to confirm this (P. Raust in litt. 2007).

Ecology

Although once thought to be confined to remaining undisturbed forest fragments in valleys and mountains between 40 and 450 m (292 ha in 1991), and not able to utilise coastal vegetation or secondary forest (Thibault and Varney 1991), it has been seen in pine plantations and may feed on the introduced Chinese guava Psidium cattleianum (P. Raust in litt. 2007). It feeds on fleshy fruit and nectar from flowers (Thibault and Varney 1991).

Threats

Destruction and degradation of forest by goats, cattle, fires (used to control fernland and increase grazing land) and felling are the main threats. Predation by feral cats and Polynesian rat Rattus exulans are possible threats, while hunting for food by local inhabitants is no longer a threat owing to an improvement in the standard of living on the island (Thibault and Varney 1991).

Conservation actions

Conservation and Research Actions Underway
Proposals have been made to protect the Hiri Valley and to consider captive breeding (Thibault and Varney 1991). Guava trees have become established on the island, these may reduce the impact of cattle grazing on the species's habitat and provide a new food source (J. Millet in litt. 2007, P. Raust in litt. 2015).

Conservation 
and Research Actions ProposedRe-survey the population. Study the level of use of P. cattleianum and its impacts on occupancy and population trends. Discuss with the local community the possibility of establishing a protected area in the upland forests - if agreement is reached, fence forest remnants to reduce grazing pressure (SPREP 1999). Reduce goat numbers (SPREP 1999). Exclude fires from upland areas (SPREP 1999). Consider the possibility of translocation to another island to establish a second population (SPREP 1999). Investigate the impact of cats and rats on the species, and take precautions to prevent invasion by black rat Rattus rattus. As a precaution, establish a captive population.

Identification

31 cm. Medium-sized, mostly green pigeon, larger and longer tailed than most fruit-doves. Feathers of lower chest cloven producing rows of shadows that appear as streaks. Pale blue-grey foreparts (head, neck, chest, upper back) shading into green of body above. Yellowish-white tip of tail, not sharply demarcated. Bright rose crown, face and throat, dark rose undertail-coverts. Yellow lower belly and edges of wing feathers. Rose-purple band below cloven chest feathers. Yellow bill and iris. Red legs. Voice Repetitive series of double oo-wa notes.

Acknowledgements

Text account compilers
Ashpole, J, Derhé, M., Dutson, G., Mahood, S., O'Brien, A., Pilgrim, J., Stattersfield, A.

Contributors
Millett, J., Kesler, D., Raust, P.


Recommended citation
BirdLife International (2017) Species factsheet: Ptilinopus huttoni. Downloaded from http://www.birdlife.org on 21/09/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 21/09/2017.