Justification of Red List Category
This species has not been recorded with certainty on Kaua'i since 1989 nor on Hawai'i since 1987, and recent searches specifically for it have failed. It may have been driven extinct by habitat loss, introduced rats, and in particular from malaria from introduced mosquitoes. However, it cannot yet be presumed to be Extinct until all potential areas have been surveyed, particularly in Ka`u, Waiakea, and Pu`u Maka`ala, and recent unconfirmed reports have been followed up by systematic searches. Any remaining population is likely to be tiny, and for these reasons it is treated as Critically Endangered (Possibly Extinct).
Any remaining population is assumed to be tiny (numbering fewer than 50 individuals and mature individuals), with unconfirmed reports since 1995, but no confirmed records since 1989.
Given the paucity of recent confirmed reports of this species, it is very difficult to assess the population trend, and essentially the trend is unknown.
Psittirostra psittacea was originally widespread in the Hawaiian Islands (USA), but was extirpated from O`ahu, Maui, Moloka`i and then Lana`i between 1899 and 1931 (Snetsinger et al. 1998). On Kaua`i, it survived in the Alaka`i Wilderness Preserve into the mid-1970s, with c.62 birds being present during 1968-1973 (USFWS 1983), but only a few in 1981 (Scott et al. 1986), two in 1989 and none since. On Hawai`i, several populations were present in the early 1980s, with c.394 estimated during 1976-1983 (Scott et al. 1986) but, in 1984, a lava-flow from Mauna Loa passed through the Upper Waiakea Forest Reserve, the species's stronghold (Scott et al. 1986, Snetsinger et al. 1998), and the last confirmed sighting was in 1987 (Snetsinger et al. 1998). However, since 1995 there have been unconfirmed reports from Koai`e Stream, Alaka`i (Kaua`i) and Pu`u Maka`ala Natural Area Reserve and Kapapala-Ka`u Forest Reserve (Hawai`i) (Snetsinger et al. 1998, J. Lepson in litt. 1999). The prognosis is poor, especially given the species's preference for lower elevations where habitat loss and the impacts of introduced disease and predators have been most severe, but it cannot yet be presumed to be Extinct until the last areas have been intensively surveyed (S. Fretz, E. Vanderwerf, R. Camp and M. Gorresen in litt. 2003). Any remaining population is likely to be tiny.
It is restricted to wet to mesic `ohi`a forest between 800 and 1,900 m, mainly 1,200-1,500 m (Scott et al. 1986, Snetsinger et al. 1998). Its bill is adapted to feeding on `ie`ie, an understory vine, and outside the `ie`ie fruiting season, it is nomadic in response to seasonal fruit and invertebrate abundance (Snetsinger et al. 1998).
Habitat has been lost and modified by logging and agriculture, and `ie`ie has declined because of pressure from introduced rats and ungulates (Snetsinger et al. 1998). Feral pigs, in particular, are pervasive habitat degraders (Scott et al. 1986, Anderson and Stone 1993, Pratt 1994) and their activity benefits the introduced mosquito vectors of avian diseases which are implicated in the rapid decline of this species (Scott et al. 1986, Pratt 1994, Snetsinger et al. 1998), especially given that its nomadic behaviour may increase its exposure to disease (Snetsinger et al. 1998). The population has been decimated by hurricanes on Kaua`i and lava-flows on Hawai`i (Conant et al. 1998, Snetsinger et al. 1998).
Conservation Actions Underway
Recent reports of this species come from three protected areas (Snetsinger et al. 1998). A Rare Bird Search Project was implemented to find the species and make recommendations for its conservation, but none were located (Snetsinger et al. 1998). Feral pig elimination is being carried out in a number of protected areas in Hawai`i (Anderson and Stone 1993) which could hold remnant populations. The Kaua`i Watershed Alliance and The Nature Conservancy are considering fencing (to exclude herbivores and possibly other predators) the north-eastern section of the Alakai Plateau on Kaua`i, where the species was last recorded.
17 cm. Chunky finch with thick bill strongly hooked at tip. Male olive-green with sharply defined yellow head and white undertail-coverts. Female olive-green above and below, greyer on throat and upper breast. Bill pink in both sexes. Voice Song long, loud and complex with whistles, trills, and warbles. Call an upslurred or downslurred whistle, very far-carrying.
Text account compilers
Stattersfield, A., Butchart, S., Benstead, P., Stuart, T., Symes, A., Westrip, J., Derhé, M., Bird, J., Isherwood, I.
Camp, R., Fretz, S., Gorresen, M., Pratt, T., VanderWerf, E., Woodworth, B. & Lepson, J.
BirdLife International (2020) Species factsheet: Psittirostra psittacea. Downloaded from http://www.birdlife.org on 15/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/08/2020.