Data Zone
Justification of Red List category
This species qualifies as Vulnerable as it is only found on one small island where it remains at risk from the accidental introduction of exotic species.
Population justification
Estimates over the past three decades have been broadly congruent. In 1987, the population was estimated at c.3,420 individuals (Graves 1992; adjusted to 3,070 individuals using the correct island area, and assuming 75% habitat suitability; Brooke and Jones 1995) and, in 1992, using a different technique, at c.3,150 (adjusted to 3,650 using correct island area). In 2015, the population at 25 point count localities was extrapolated to the area of suitable habitat, enumerating to a population size of 4,476-10,072 (Bond et al. 2019a). Because the latter estimate was based on detectability distances that were not empirically determined, the value from Brooke and Jones (1995)—who approximated territory size—is considered the most accurate determination of the number of mature individuals, set here to 3,000-4,000.
Trend justification
Although direct comparison is hampered by methodological differences, count data between 1987 and 2015 are comparable (Graves 1992, Brooke and Jones 1995, Bond et al. 2019a) and do not indicate any decline. Since 2015, there is no identified threat that may have caused a reduction, although it is acknowledged that the population size of this species moderately fluctuates in response to food availability (Brooke and Jones 1995).
Ptilinopus insularis is confined to Henderson in the Pitcairn Islands (to UK), a small uninhabited, raised-reef island in the south-central Pacific Ocean.
The species inhabits interior forest, with dense understorey. It is a specialist frugivore (possibly territorial so that it can exploit fruits as they become available), foraging solitarily or in pairs (Brooke and Jones 1995). Research in 1991/1992 recorded 19 different plants in its diet, with Procris pedunculata constituting the major food. A preference for fruit with a high water content suggests that the species may rely on its food for obtaining water, especially during dry spells (as there is no permanent water on Henderson) (Brooke and Jones 1995). From two nests, each with a single egg recorded in March, the breeding season would appear to be at the beginning of the calendar year and clutch-size is probably one (Brooke and Jones 1995).
Although Polynesian Rat Rattus exulans may take eggs and chicks, there is no indication that the species is unduly threatened by this predation as the two have co-existed on Henderson possibly since the 8th century (Jones et al. 1995). In August 2011, an attempt was made to eradicate R. exulans from Henderson island, but this failed and rat populations recovered by 2013 (Churchyard et al. 2013). Other possible introductions, such as other Rattus species (e.g. R. rattus or R. norvegicus) could cause rapid future declines and extinction, as they have other insular Columbid populations. Diseases and exotic plant species are also potential future threats (Waldren et al. 1995).
Conservation Actions Underway
In 1988, Henderson was designated a World Heritage Site. Following a feasibility study (Brooke and Towns 2008) a rat eradication operation was attempted on Henderson Island in August 2011, but this failed and rat density returned to pre-eradication levels by 2013 (Churchyard et al. 2013, Bond et al. 2019b).
22 cm. Small, basically two-toned pigeon. Crown and forehead bright rose-red narrowly bordered by golden-yellow. Pale blue-grey head, neck, upper back, and chest. Rest of body olive-green, paler below with yellow undertail-coverts. Tail with bronzy reflections above, tipped white. Wing feathers edged yellow, tending to white on tertials. Yellow-green bill. Orange-red iris and feet. Voice A coarse coo.
Text account compilers
Berryman, A.
Contributors
Bell, B., Bond, A., Brooke, M., Hall, J. & Oppel, S.
Recommended citation
BirdLife International (2024) Species factsheet: Henderson Island Fruit-dove Ptilinopus insularis. Downloaded from
https://datazone.birdlife.org/species/factsheet/henderson-island-fruit-dove-ptilinopus-insularis on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/12/2024.