CR (PE)
Oahu Alauahio Paroreomyza maculata



Justification

Justification of Red List Category
The last well-documented observation of this species was in 1985, and recent searches specifically for the species have failed. It may have been driven extinct by disease spread by introduced mosquitoes. However, it cannot yet be presumed to be Extinct until all areas of remaining habitat have been thoroughly searched. Any remaining population is likely to be tiny, and for these reasons it is treated as Critically Endangered (Possibly Extinct).

Population justification
Any remaining population is assumed to be tiny (numbering fewer than 50 individuals and mature individuals), with the last probable sighting in 1985, despite recent searches for the species.

Distribution and population

Paroreomyza maculata is endemic to O`ahu in the Hawaiian Islands (USA), where fossil evidence indicates that it once occurred in the lowlands (Olson and James 1982). In the past few decades, there have only been a few confirmed sightings, with several of these from the area around North Halawa Valley, Ko`olau range (Pratt 1993). However, many recent records are viewed with doubt because of its close similarity with Hemignathus flavus. The last well-documented observation was of two birds on 12 December 1985 on Poamoho Trail during the Waipi`o Christmas Bird Count (Bremer 1986); the last specimen was taken in 1968 and some consider this the last definitive record (Roberts et al. 2010). There have been several reports from different areas since, but details of the observations have been inconclusive and the birds were never relocated. However, it cannot yet be presumed to be Extinct until further surveys have confirmed that there is no reasonable doubt that the last individual has died. If any population remains, it is likely to be tiny.

Ecology

In the 1890s, it was reported to eat quantities of carabid beetles, most likely wood-borers, as it was seen feeding on the dead branches of koa trees (Berger 1972). Recent sightings have been between 300 and 650 m in remnant native, lowland mesic to wet forest (Baker and Baker 2000). One nest with two eggs was collected in late January 1901 (Berger 1972).

Threats

Some native forests remain on O`ahu, so habitat loss and alteration cannot fully explain the decline of this species (VanderWerf et al. 1997). Disease spread by introduced mosquitoes is prevalent in the lowlands (Lindsey et al. 1998) and is a likely contributory factor. Circumstantial evidence links declines of some native birds on O`ahu with the spread of introduced birds, but there is no direct evidence for their impact (Scott et al. 1986, VanderWerf et al. 1997) and, as this species probably feeds primarily on wood-boring insects, introduced birds are unlikely to be significant competitors. The construction of the H-3 freeway (for which the US Congress gave specific exemption from the Endangered Species Act) destroyed habitat around North Halawa Valley, from which some of the most recent confirmed sightings have come (Pratt 1993, J. Lepson in litt. 1999).

Conservation actions

Conservation Actions Underway
Surveys have been carried out during the 1990s to search for this species, but have failed to find any birds (Pratt 1994). A Rare Bird Discovery Protocol has been developed which could be applied to this species in the event of its rediscovery (US Fish and Wildlife Service 2006).

Conservation Actions Proposed
Continue to conduct intensive and extensive surveys to locate any remaining populations (Baker and Baker 2000), following similar methods to the Hawaii Rare Bird Search (Reynolds and Snetsinger 2001). If any birds are found, start intensive monitoring, including the collection of data on vocalisations, foraging and breeding behaviour (Baker and Baker 2000). If active nests are found, ensure localised predator control (Baker and Baker 2000). Consider captive propagation, following development of specific techniques (Baker and Baker 2000).

Identification

11 cm. Small, straight-billed, warbler-like passerine. Male yellow below, olive-green above, with dark lores fading into olive eye-stripe, and distinct yellow forehead and superciliary. Female greenish-grey above, pale yellowish-white below, with two prominent, pale wing-bars, pale lores and forehead, and dark eye-stripe. Similar spp. Both sexes of O'ahu `Amakihi Hemignathus flavus have dark forehead, curved bills, and no pale superciliary. Introduced Japanese White-eye Zosterops japonicus has bold white eye-ring. Voice Song unknown. Call a loud cherk.

Acknowledgements

Text account compilers
Benstead, P., Bird, J., Butchart, S., Derhé, M., Isherwood, I., Stattersfield, A., Stuart, T. & Symes, A.

Contributors
Camp, R., Fretz, S., Gorresen, M., Lepson, J., Nelson, J., VanderWerf, E. & Woodworth, B.


Recommended citation
BirdLife International (2020) Species factsheet: Paroreomyza maculata. Downloaded from http://www.birdlife.org on 22/10/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/10/2020.