Data Zone
Justification of Red List category
This species formerly occurred on three islands, but survives on only one where its very small population is apparently stable, but at risk from habitat degradation by sheep and predation by cats. The accidental introduction of Black Rats (Rattus rattus) is also a critical concern, as this contributed to the extinction of the species on other islands. It therefore qualifies as Endangered.
Population justification
Estimations of this species' population size have slightly varied, but there remains a reasonable probability it numbers fewer than 250 mature individuals. In 2000, the population was estimated 80-125 pairs (i.e. 160-250 mature individuals) based on a density of 4-5 pairs/10 ha in Pisonia forest (Thibault and Meyer 2001). In 2019, a more thorough exercise of territory mapping all accessible parts of the islands identified 302 birds (including young birds) and 109 pairs, with 330-500 birds estimated across the entire island (Blanvillain et al. 2019). The population is therefore considered to number 220-330 mature individuals.
Trend justification
The population appeared healthy in 2019 (Blanvillain et al. 2019) as in 2006 (P. Raust in litt. 2007) and is estimated to be stable or increasing due to the extension of the Pisonia forest (C. Blanvillain in litt. 2020).
Pomarea mendozae was formerly widespread in the central Marquesas Islands, French Polynesia, occurring as two subspecies on three islands. On Hiva Oa, the now-extinct nominate mendozae was common in 1921 and 1922, and was last seen in March 1975, when only one individual was seen despite several weekly field searches. It was not seen in 1990, 1996 or in 2000 (Thibault and Meyer 2001), and two recent records of single birds (Anon. 1999) are considered erroneous. The subspecies also occurred on Tahuata. It was apparently common in 1922 but it was not found in 1975 or 1990 (Thibault and Meyer 2001). The species now survives only on Mohotani.
This mainly insectivorous species occurred in forested valleys at high elevations and in degraded forest at all altitudes (probably originally preferring lowland forests which are now destroyed). On Mohotani, it is found in dry forest with Pisonia grandis (Holyoak and Thibault 1984). Adults apparently prefer areas of dense, luxuriant vegetation while immatures often frequent shrubby vegetation in dry areas (Holyoak and Thibault 1984).
On Mohotani, feral cats Felis catus are a threat and, to a lesser extent, Polynesian rat Rattus exulans, as well as intense grazing by feral sheep (Seitre and Seitre 1991, 1992). All the Marquesas Islands have been devastated by intense grazing and fire, and much of the original dry forest has been reduced to grassland, and upland forest to relict forest patches. On all islands, introduced species have been a threat, especially black rat Rattus rattus and (which is not, thankfully, yet present on Mohotani), on Hiva Oa, introduced birds such as the predatory Great Horned Owl Bubo virginianus and the very competitive Common Myna Acridotheres tristis. Avian malaria represents a legitimate risk, with the same strain that has impacted many Hawaii endemic bird species present on Nuku Hiva, and Avian Pox was observed in Ua Pou (C. Blanvillian in litt. 2020).
Conservation Actions Underway
Mohotani has been protected since 1971. However, the banning of hunting has resulted in serious degradation by an increasing population of feral sheep (SPREP 1999). Preparation of a management plan, involving people from nearby islands (sheep hunters and wood carvers) was begun in 2007 but islanders were not ready to accept sheep eradication from this island in 2018 (T. Withers pers. comm. 2020). Long term management of this threat, with a regular control of sheep, resulted in an amelioration of the habitat and the extension of the Pisonia forest in 2019, and probably a related increase of the monarch population. A feasibility study for the eradication of rats and cats on Mohotani is ongoing (C. Blanvillain in litt. 2020).
Conservation Actions Proposed
Carry out regular surveys to monitor population trends. Consider possibilities of translocation and the establishment of a captive breeding population. On Mohotani, eliminate or control feral sheep if socially acceptable (SPREP 1999). If it is not possible to reduce sheep numbers, fence part of the island to prevent grazing and allow habitat regeneration/restoration (SPREP 1999). Eradicate cats and rats (SPREP 1999). Take precautions to prevent invasion by black rat R. rattus. Eradicate B. virginianus and A. tristis. Estimate the threat represented by exotic diseases that may be introduced by invasive birds. Collar and Butchart (2013) suggested that captive breeding should be considered, especially if/when translocations are considered.
Text account compilers
Berryman, A.
Contributors
Raust, P., Allanic, Y. & Gouni, A.
Recommended citation
BirdLife International (2024) Species factsheet: Marquesas Monarch Pomarea mendozae. Downloaded from
https://datazone.birdlife.org/species/factsheet/marquesas-monarch-pomarea-mendozae on 22/11/2024.
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 22/11/2024.