Data Zone
Justification of Red List category
This species has a very small breeding range, and is only known to breed on four tiny islets around Rapa, French Polynesia, but potentially also on the main island. The population is undergoing a drastic decline, presumably as a result of depredation by introduced mammals. Therefore, this newly-split species is listed as Critically Endangered.
Population justification
In 1974 the population size was estimated at 265-380 pairs (excluding any potential birds breeding on the main Rapa Island), but no individuals were located during surveys in 1989 (Thibault and Varney 1991). A survey of Morotiri found no individuals of this taxon (Gaskin et al. 2006), and a visit to Rapa in 2017 found only a very small number of individuals (though this was likely not during the breeding season) (S. Cranwell per M. O’Brien in litt. 2018). At sea surveys find the occasional individual, but it appears highly unlikely that there 500-800 mature individuals remaining (M. O’Brien in litt. 2018). The population size is tentatively placed in the band 50-249 mature individuals, equating to 75-375 individuals in total, although it potentially could be lower than this.
Trend justification
While it is likely that the threats this species faces are causing declines, there is no clear evidence of the rate of decline.
Rapa Shearwater is only known to breed on four tiny islets around Rapa, French Polynesia, with a potential breeding population in the interior of the main island (Thibault and Varney 1991, Shirihai et al. 2017, del Hoyo et al. 2018).
The species nests in burrows on four tiny islets around Rapa.
There is limited data available about the threats facing this recently recognised taxon. Historically, seabird chicks were harvested for food by local people on Rapa. Petrels appear to have been a more popular target, but the records of harvest for the beginning of the 20th century up until 1970, also include Christmas Shearwaters Puffinus nativitatis (Thibault and Varney 1991) and it is not unlikely that some Rapa Shearwaters were also taken. Hunting is now discontinued, due to improved standards of living and the availability of imported food on the island.
The species is potentially at risk from invasive predators, but currently, only Polynesian Rats Rattus exulans are likely to be present in the species’ range. Rats occur on the mainland, and in synergy with cat predation and grazing by goats (Thibault and Varney 1991), it is possible that they caused the extirpation of a suspected past population breeding on the main island, and prevent recolonization. Excavated bones suggest that the species once inhabited the main island (Tennyson and Anderson 2012). Other candidate drivers for a possible extinction from the main island include habitat degradation through land clearance for agriculture (Thibault and Varney 1991).
Conservation Actions Underway
None known.
33 cm. Medium-sized shearwater, generally black above and white below. Undertail-coverts white basally, black distally, therefore appearing white (the last is the most useful field character). Similar spp. Townsend's Shearwater P. auricularis, but little or no range overlap. Hints Feeds at ocean fronts along the Equatorial Counter Current. Typical low fast flight of smaller shearwaters, but wingbeat slower than Audubon's Shearwater P. lherminieri.
Text account compilers
Fjagesund, T., Westrip, J., Hermes, C., Stuart, A.
Contributors
Cranwell, S., O'Brien, M.
Recommended citation
BirdLife International (2024) Species factsheet: Rapa Shearwater Puffinus myrtae. Downloaded from
https://datazone.birdlife.org/species/factsheet/rapa-shearwater-puffinus-myrtae on 22/12/2024.
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 22/12/2024.