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Drepanis coccinea 

Scope: Global
Language: English
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_onStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Fringillidae

Scientific Name: Drepanis coccinea
Species Authority: (Forster, 1781)
Common Name(s):
English Iiwi, 'I'iwi
Synonym(s):
Vestiaria coccinea (Forster, 1780)
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.

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(i,ii,iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Camp, R., Donaldson, P., Fretz, J., Lepson, J., Pratt, H., Roberts, P., VanderWerf, E., Hart, P., Costantini, M. & Crampton, L.
Facilitator/Compiler(s): Benstead, P., Derhé, M., O'Brien, A., Stuart, T., Taylor, J. & North, A.
Justification:
This species is listed as Vulnerable because it has a small and contracting range and, although it is still relatively abundant, surveys have shown that it is undergoing a continuing population decline.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Vestiaria coccinea formerly occurred on all the main islands in the Hawaiian Archipelago (USA) but it is now extinct on Lana'i and relict populations (probably fewer than 50 individuals [J. Lepson in litt. 2000]) remain on O`ahu and Moloka`i (Scott et al. 1986, P. Donaldson in litt. 1999). Recent population estimates are: c.385,000 individuals, excluding birds on O`ahu, during 1976-1983 (Scott et al. 1986) and more than 350,000 individuals in the early 1990s following recent declines in several populations (Jacobi and Atikinson 1995). There is now evidence from monitoring (much of it unpublished) that the species has declined throughout the Hawaiian islands, except on windward Mau`i and at Hakalau, Hawai`i, where the populations appear to be stable (D. Pratt in litt. 2007). The numbers of individuals detected during monitoring have fallen at both mid and low elevations (D. Pratt in litt. 2007). The apparent decline appears to have been most pronounced in western Hawai`i, and on Kaua’i where the population has declined by 86% (D. Pratt in litt. 2007, Paxton et al. in press). Habitat modeling predicts that the species will lose 59.9% of its range across Hawai’I, and 100% of its range on Kaua’i (Fortini et al. 2015). 

Countries occurrence:
Native:
United States (Hawaiian Is.)
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:19800
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:6Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):1300
Upper elevation limit (metres):1900
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:

An estimate of more than 350,000 individuals was made in the early 1990s (Jacobi and Atikinson 1995). On Kaua’i, the population estimate has declined greatly since 2000, and is at approximately 2,603 individuals (Paxton et al. in press). 



Trend Justification:  The population is declining (figures still to be published), owing to avian malaria and other factors.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:100

Habitat and Ecology [top]

Habitat and Ecology:This species was formerly found in forests at any elevation, and still occurs in a variety of native, disturbed and unnatural habitats from 300 to 2,900 m (Berger 1972, Scott et al. 1986). The greatest densities are found at 1,300-1,900 m, and low elevation populations may be sustained primarily by dispersal from mid-elevation populations (Scott et al. 1986). Evidence for hybrization with another honey creeper, the 'Apapane Himatione sanguinea has recently been documented (Knowlton et al. 2014).

Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):4.9
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): The exact causes for the decline are uncertain, although it is known that the species is very susceptible to avian malaria (Jacobi and Atikinson 1995, D. Pratt in litt. 2007). Research on the Alaka’i Plateau found the species to have very low malaria prevalence, with just one infected individual detected in 1994 and none in the period 2007-2013, whilst research at Hakalau found an increase in malaria prevalence from 0% in 1988-1992 to 8% in 2001-2002 (VanderWerf 2012). Increased temperatures associated with climate change may influence the prevalence of malaria in this species (Freed et al. 2005). Other factors which are likely to be contributing to its decline include habitat degradation and predation by introduced mammals such as cattle, pigs, cats and rats. Invasive plants degrading habitat include strawberry guava (Psidium cattleianum) (VanderWerf 2012). Observed increases in chewing lice may have impacts on time spent foraging and survival, though further research is needed to fully understand this potential threat (Freed et al. 2008).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The species is the subject of population trend analysis and detailed studies into the effects of avian malaria by the U.S. Geological Survey Pacific Island Ecosystems Research Centre. A habitat suitability map for this species on Kaua’i will also be made following the acquisition of LiDAR in 2016. Actions not directly aimed at the Iiwi will also be benefitting this species, such as ungulate removal and control of alien plant species (VanderWerf 2012).

Conservation Actions Proposed
Complete assessment of current population trends. Study the factors driving the decline. Attempt to mitigate against the decline, including efforts to control mosquito populations. 


Citation: BirdLife International. 2016. Drepanis coccinea. The IUCN Red List of Threatened Species 2016: e.T22720844A94686315. . Downloaded on 11 December 2016.
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