• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species may prove to be the only member of its genus whose habitat and population size have, so far, been little affected by adverse changes to its environment. However, it qualifies as Vulnerable as it has a small population (thought to be <1,000 mature individuals) found only on one small island where it is at risk from the accidental introduction of alien species.

Population justification
The population has most recently (in 2015) been estimated at 554-3,014 birds, or c.360-2,000 mature individuals based on point counts at 25 locations and extrapolated across the island (assuming 75% of habitat was suitable) using binomial mixture models  (Bond et al. 2019a). However, the species is very mobile across the island making accurate population estimates difficult (Oppel and Bond in litt. 2016, Bond et al. 2019a). The best estimate is here placed at 500-1,000 mature individuals given reports of the species's mobility.

Trend justification
The population in 1987 was estimated at 646-1,616 individuals (Graves 1992) when applied to the correct island area (see Bond et al. 2019a) and assuming the entire island was suitable. In 2015, the population size was estimated to be 554-3,014 birds assuming 75% of the island area was suitable. Although caution is exercised given the unreliability of estimating the population size of this species because it is so mobile (Bond et al. 2019a), these data suggest that the population has remained broadly stable. Although the species appears comparatively unimpacted by the presence of Pacific rats (Rattus exulans), such that even during an attempted eradication the population of V. stepheni did not substantially increase (unlike other species studied) (Bond et al. 2019a), it may suffer precipitously if larger Norway rats (R. novergicus) were accidentally introduced.

Vini stepheni is restricted to Henderson in the Pitcairn Islands (to UK), a small uninhabited, raised-reef island in the south-central Pacific Ocean. 

It occurs in native forest (often observed at the forest edge), and in coconut palms along beaches. It is a generalist feeder, consuming nectar, pollen and fruit from a wide variety of plants from beach-level to the plateau, although flowers from the plants Scaevola sericea and Timonius polygamus provide the main sources of nectar (Trevelyan 1995). Arthropods form part of the diet, including lepidopteran larvae found in the sporangia of the fern Phymatosorus (Trevelyan 1995).

This species appears little affected by the only introduced predator, Pacific rat Rattus exulans (Trevelyan 1995), but a larger rat species (e.g. R. rattus or R. norvegicus) or other alien predator is thought likely to cause greater damage (Bond et al. 2019a) as they have for other insular parrot species. In August 2011, a rat eradication operation was attempted on Henderson Island to eradicate R. exulans from the island but the attempt failed and rat density returned to pre-eradication levels by 2013 (Bond et al. 2019b). Introduced diseases such as avian malaria and pox are another potential threat. The introduction of exotic plant species could have serious consequences for the native vegetation (Waldren et al. 1995) and therefore for this species.

Conservation Actions Underway
CITES Appendix II. In 1988, Henderson was designated a World Heritage Site. Following a feasibility study (Brooke and Towns 2008) a rat eradication operation was carried out on Henderson island in August 2011; the attempt failed and rat density returned to pre-eradication levels by 2013 (Bond et al. 2019b); the number of lorikeets appeared to be unimpacted (Bond et al. 2019a).

Conservation Actions Proposed
Periodically resurvey to monitor numbers and trends. Ensure that further alien species are not accidentally introduced to Henderson. Re-attempt the eradication of Pacific rats from Henderson. 

18 cm. Red-and-green parakeet. Dark green above shading to golden-yellow tip of tail. Red on cheeks and underparts, dark purple central belly. Belt across chest green at sides, purple in centre. Golden-yellow bill and eyes. Voice A shrill screech.

Text account compilers
Berryman, A., Stattersfield, A., Shutes, S.

Contributors
Brooke, M., Hall, J., Bell, B., Bond, A. & Oppel, S.

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Recommended citation
BirdLife International (2024) Species factsheet: Henderson Lorikeet Vini stepheni. Downloaded from https://datazone.birdlife.org/species/factsheet/henderson-lorikeet-vini-stepheni 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.