Taxonomic note
Hemignathus wilsoni (del Hoyo and Collar 2016) was previously listed as H. munroi following AOU (1998 & supplements); Sibley & Monroe (1990, 1993).
Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Critically Endangered | Endangered | Vulnerable |
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- | B1ab(i,ii,iii,iv,v) | B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); D2 |
Year | Category | Criteria |
---|---|---|
2023 | Endangered | B1ab(i,ii,iii,iv,v) |
2016 | Endangered | B1ab(i,ii,iii,iv,v); C2a(ii) |
2013 | Endangered | B1ab(i,ii,iii,iv,v) |
2012 | Endangered | B1ab(i,ii,iii,iv,v) |
2008 | Endangered | B1a+b(i,ii,iii,iv,v) |
2004 | Endangered | |
2000 | Endangered | |
1996 | Endangered | |
1994 | Endangered | |
1988 | Threatened |
Migratory status | not a migrant | Forest dependency | high |
Land-mass type | Average mass | - |
Estimate | Data quality | |
---|---|---|
Extent of Occurrence (breeding/resident) | 1,300 km2 | medium |
Area of Occupancy (breeding/resident) | 832 km2 | |
Number of locations | 1 | - |
Severely fragmented? | no | - |
Estimate | Data quality | Derivation | Year of estimate | |
---|---|---|---|---|
Population size | 1300 mature individuals | good | estimated | 2009 |
Population trend | decreasing | good | inferred | - |
Generation length | 3.34 years | - | - | - |
Number of subpopulations | 2 | - | - | - |
Percentage of mature individuals in largest subpopulation | 1-89% | - | - | - |
Population justification: In 1976-1979 and 1983, surveys estimated c.1,500 birds, with 900 in Hamakua, 500 in Ka`u, 50 on Mauna Kea, and 20 in central Kona (Scott et al. 1986). In 1990-1995, surveys estimated 1,163, with 1,105 in Hamakua, c.44 in Ka`u, fewer than 10 on Mauna Kea (and only a few males by 1999 [T. Pratt in litt. 1999]), and perhaps fewer than 10 in Kona (Fancy et al. 1996). The population on western Mauna Kea has since been extirpated (VanderWerf 2012). The species' population in Ka`u was estimated at 1,073 individuals (95% CI: 616-1,869) in 2005 (Gorresen et al. 2007). It should be noted that this higher population estimate in Ka`u does not represent a genuine population increase, but an improvement in survey methodology. Surveys conducted during 2003-2004 in the Kapapala Forest Reserve reported 35 individuals (including 14 families) in c. 650 ha of the reserve (Pratt et al. 2009). The population at the Kona Forest National Wildlife Refuge may also now be extirpated (Fancy et al. 1996, Camp et al. 2009). The global population was estimated at 1,900 birds in 2009 (Gorreson et al. 2009), roughly equivalent to 1,300 mature individuals overall, with 1,163 birds (95% CI: 507-2,401) occurring in Hakalau Forest National Wildlife Refuge (Kendall et al. 2022).
Trend justification: Surveys in 1990-1995 suggested a decline of c.22.5% over the previous 13 years (Fancy et al. 1996). The species is extirpated from subalpine Mauna Kea and likely Kona districts (Gorresen et al. 2009). Surveys from 1977 to 2003 indicate that the species may have declined in the Keauhou-Kulani area (Gorresen et al. 2005). In the Ka`u District of Hawai`i, surveys from 1976 to 2005 indicate that the species has been extirpated from habitat below 1,500 m, with no change in the density of populations at high elevations (Gorresen et al. 2007). Trends at Hakalau Forest National Wildlife Refuge and in the upper portions of the Ka‘? Forest Reserve were previously thought to be increasing and stable, respectively (Camp et al. 2009, 2010). In a recent analysis of annual population density estimates in Hakalau Forest National Wildlife Refuge, which supports c.61% of the population, trends were negative in the closed-forest stratum in the period 1987-2019. In the most recent decade 2010-2019, density declined by more than 10% in the closed-forest stratum, although the trend was inconclusive for open-forest and increasing in restored pasture (Kendall et al. 2022). Trends are unknown in central windward Hawai‘i and Ka‘? regions (USFWS 2020). The population is inferred to be declining overall given ongoing range contraction, and this is predicted to continue given that the threats are ongoing. Given that the species is highly susceptible to avian malaria, climate change is likely to reduce the area of suitable remaining habitat and drive further declines through causing an increase in the elevation below which regular transmission occurs (USWFS 2020).
Country/Territory | Presence | Origin | Resident | Breeding visitor | Non-breeding visitor | Passage migrant |
---|---|---|---|---|---|---|
USA | extant | native | yes |
Country/Territory | IBA Name |
---|---|
USA | Hamakua Forests |
USA | Kau Forest |
USA | Mauna Loa-Kilauea Forests |
Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
---|---|---|---|
Forest | Subtropical/Tropical Dry | major | resident |
Forest | Subtropical/Tropical Moist Montane | major | resident |
Altitude | 1300 - 2100 m | Occasional altitudinal limits | (max) 2900 m |
Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
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Agriculture & aquaculture | Livestock farming & ranching - Agro-industry grazing, ranching or farming | Timing | Scope | Severity | Impact | ||||
Past, Unlikely to Return | Majority (50-90%) | Slow, Significant Declines | Past Impact | ||||||
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Biological resource use | Logging & wood harvesting - Unintentional effects: (large scale) [harvest] | Timing | Scope | Severity | Impact | ||||
Past, Unlikely to Return | Majority (50-90%) | Slow, Significant Declines | Past Impact | ||||||
|
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Climate change & severe weather | Habitat shifting & alteration | Timing | Scope | Severity | Impact | ||||
Ongoing | Whole (>90%) | Slow, Significant Declines | Medium Impact: 7 | ||||||
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Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Felis catus | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
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Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Plasmodium relictum | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
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Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Rattus rattus | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
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Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Sus domesticus | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
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Invasive and other problematic species, genes & diseases | Invasive non-native/alien species/diseases - Unspecified species | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
|
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Invasive and other problematic species, genes & diseases | Problematic native species/diseases - Unspecified species | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
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Invasive and other problematic species, genes & diseases | Problematic species/disease of unknown origin - Named species | Timing | Scope | Severity | Impact | ||||
Ongoing | Unknown | Unknown | Unknown | ||||||
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Invasive and other problematic species, genes & diseases | Viral/prion-induced diseases - Avipoxvirus | Timing | Scope | Severity | Impact | ||||
Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
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Recommended citation
BirdLife International (2024) Species factsheet: Akiapolaau Hemignathus wilsoni. Downloaded from
https://datazone.birdlife.org/species/factsheet/akiapolaau-hemignathus-wilsoni on 24/12/2024.
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 24/12/2024.