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Hemignathus parvus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AVES PASSERIFORMES FRINGILLIDAE

Scientific Name: Hemignathus parvus
Species Authority: (Stejneger, 1887)
Common Name(s):
English Anianiau, 'Anianiau
Synonym(s):
Viridonia parva parva Collar et al. (1994)
Viridonia parva parva Sibley and Monroe (1990, 1993)

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Camp, R., Fretz, S., Gorresen, M., Lepson, J., Pratt, H., Roberts, P., VanderWerf, E. & Woodworth, B.
Facilitator/Compiler(s): Benstead, P., Derhé, M., Isherwood, I., Stattersfield, A., Stuart, T., Taylor, J.
Justification:
This species qualifies as Vulnerable because it has a very small range. It survives in a very small occupied area of upland forest on one island, where it is at risk from the effects of exotic taxa. It is close to qualifying as Endangered, but appears able to tolerate some disturbance to its habitat.

Geographic Range [top]

Range Description: Hemignathus parvus is endemic to Kaua`i in the Hawaiian Islands (USA), where it occurred almost throughout the island in the 19th century but, by 1900, had become uncommon to rare in lowland forests (Lepson 1997). In 1968-1973, surveys estimated 24,230 birds, largely restricted to upper elevations (USFWS 1983). Surveys of the Alaka`i and Kôke`e areas in 2000 yielded an estimate of c.34,500 individuals in these areas (Foster et al. 2004). In 1992, Hurricane Iniki devastated forests throughout Kaua`i and all bird populations on the island appeared to have been drastically reduced (Pratt 1993, 1994). However, it would seem that this species has recovered and appears to be increasing (Pratt 1994, Foster et al. 2004). In 2003, the total population was put at 44,359 individuals (USFWS in litt. 2003).

Countries:
Native:
United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The current population has been put at 44,359 individuals (USFWS in litt. 2003), and this is rounded to an estimate of 44,400 individuals.
Population Trend: Increasing

Habitat and Ecology [top]

Habitat and Ecology: It inhabits `ohi`a and native mixed forest mainly above 600 m, but has been found as low as 100 m (especially in the north-west of the island) (USFWS 1983, Pratt et al. 1987, Lepson 1997), although it is not known whether this is still the case (J. Lepson in litt. 1999). It is able to tolerate considerable habitat disturbance, but at lower population densities (Lepson 1997). It feeds on nectar and arthropods (especially caterpillars and spiders) and nests in `ohi`a trees (Lepson 1997).

Systems: Terrestrial

Threats [top]

Major Threat(s): From the late 1890s, significant declines have been associated with habitat loss and degradation (either owing to clearance for timber and agriculture, or to introduced herbivores), and the spread of avian diseases (Lepson 1997). Ongoing development in the Kôke`e area continues to diminish the amount of habitat available, and the spread of exotic plants into native habitats, although tolerated, is associated with lower densities (Lepson 1997). Introduced mosquitoes, which spread avian pox and malaria, are now common at 900 m, and may be breeding as high as 1,200 m elevation (Lepson 1997). Under a 2oC warming scenario and an increase in rainfall over high-elevation forests during the next 100 years, in keeping with climate model predictions for the region, the prevalence of malaria on Kaua`i is predicted to increase within the remaining habitat (Benning et al. 2002). The 17 oC isotherm, below which Plasmodium prevalence peaks, is predicted to shift upwards by around 300 m, decreasing the area of forest where Plasmodium prevalence is limited by 85% (Benning et al. 2002). Feral pigs facilitate the spread of both alien plants and mosquitoes and, with other ungulates, continue to degrade native forests (Pratt 1994). Predation by introduced animals (rats and possibly cats and Barn Owls Tyto alba) is an additional pressure (Lepson 1997), while other introduced taxa (especially the Japanese White-eye Zosterops japonicus, wasps and ants) compete for arthropod resources (Lepson 1997). Invasive plants have degraded significant portions of Kôke`e State Park and threaten the remainder of the habitat (P. Roberts in litt. 2007). This species's restriction to Kaua`i and dependence on canopy species makes it vulnerable to catastrophic events such as hurricanes (P. Roberts in litt. 2007).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Its habitat is protected in the Alaka`i Wilderness Preserve and to some extent in the Kôke`e State Park. An upper portion of the Alaka`a Wilderness Preserve is due to be fenced and ungulates will be removed from inside the fenced area, however other areas of the preserve and state park apparently lack active management (R. Camp in litt. 2007).

Conservation Actions Proposed
Monitor population trends through regular surveys. Control and prevent further introductions of non-native animals and plants, particularly in the Alaka`i Wilderness Preserve (Scott et al. 1986, Lepson 1997). Restore habitats (Lepson 1997). Identify and encourage disease-resistant lineages, e.g. by translocation, captive propagation (Lepson 1997), provision of supplementary resources, nest protection and introduced predator/competitor control.


Citation: BirdLife International 2012. Hemignathus parvus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 September 2014.
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