• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species is classified as Endangered owing to its very small and contracting range where habitat degradation is ongoing. The population is declining and highly susceptible to avian malaria, with climate change projected to cause an increase in the elevation below which regular transmission occurs.

Population justification
In 1977, the total population of Hawai‘i ‘?kepa was estimated 13,892 (95% CI + 1,825) birds (Scott et al. 1986). In 2016, total population was estimated 16,248 (95% CI 10,074 - 25,198) birds (Judge et al. 2018), roughly equivalent to 10,800 mature individuals overall, with 7,221 birds (95% CI: 4,164-11,173) occurring in Hakalau Forest National Wildlife Refuge (Kendall et al. 2022).

Trend justification

Trend analysis has previously indicated a density increase in Hakalau Forest National Wildlife Refuge in north windward Hawai‘i (Camp et al. 2016) and given recent population estimates (Scott et al. 1986, Judge et al. 2018), the species was considered stable overall (USWFS 2020). However, a more recent analysis of annual population density estimates in this area showed an overall downwards trend in the time period 1987-2019 and in the most recent decade 2010-2019, with this region supporting 44% of the global population (Kendall et al. 2022). In the period 2010-2019, density across open and closed forest decreased by approximately 30% overall (Kendall et al. 2022). The ongoing rate of decline is therefore placed in the range 25-35% within three generations (10.9 years; Bird et al. 2020). A comparison of data collected in 1987-1993 and 1999-2005 from Hakalau National Wildlife Refuge suggested the Akepa population crashed in this high-density site in 2006, as a result of increased ectoparasites and competition from Zosterops japonicus (Freed et al. 2008b). Additionally, the species is likely decreasing in central windward Hawai‘i, decreasing at Hual?lai and very small or nearly extirpated from central Kona regions (Gorresen et al. 2009, USFWS 2020). Declines are 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).

Loxops coccineus is endemic to the Hawaiian Islands, U.S.A., where it occurs as five disjunct populations in the north and central windward Hawai‘i, Ka‘ū, Kona, and Hualālai regions (USFWS 2020).

It inhabits wet and mesic forest, primarily of koa-`ohi`a at 1,100-2,100 m (mostly above 1,500 m) (Scott et al. 1986, Lepson and Freed 1997). On Hawai`i, it is an obligate cavity-nester and the highest densities are in old-growth forests, although it is also numerous in some disturbed forests with sufficient large trees. It feeds on small insects (including caterpillars) and spiders (Lepson and Freed 1997), and forages in the foliage of `ohi`a trees Metrosideros polymorpha (Freed et al. 2008b). The species has a long incubation and nestling period (14-16 and 16-20 days, respectively), a four-month fledgling period, and high annual adult survival of 0.80 (Lepson and Freed 1995, 1997).

The primary threat to this species is introduced avian disease to which it is highly susceptible, particularly avian malaria (Plasmodium relictum), causing it to have a limited distribution at higher elevations (Atkinson et al. 1995, 2000; Banko and Banko 2009). Climate change is projected to cause an increase in the elevation below which regular transmission of avian malaria occurs, reducing the area of suitable habitat and exacerbating declines (USFWS 2020). According to climate projections, due to increased rainfall and temperatures, high elevation areas for Hawaiian bird populations will only remain free of mosquitos to mid-century (Liao et al. 2015) and GIS simulation has shown that a 2 degrees Celsius increase would cause a c.100% decline in the land area where transmission is currently only periodic (Benning et al. 2002). Avian poxvirus is an additional threat, also transmitted by the non-native southern house mosquito (Culex quinquefasciatus) (VanderWerf 2012). Its habitat has been destroyed by logging and agriculture, and by commensal animals which have invaded montane forests (Scott et al. 1986, Pratt 1994, Lepson and Freed 1997). The slow growth of `ohi`a trees suggests that the large trees used for nesting are very old and so may take a long time to replace (VanderWerf 2012). This species may be more vulnerable to habitat degradation as they are considered obligate cavity nesters (Freed 2001), although there is some evidence that nesting behaviour may vary between isolated populations (Judge et al. 2018). Research has demonstrated that structural changes to habitat have affected food availability for this species (Fretz 2002). Feral ungulates, particularly pigs, have severely degraded native forests and facilitate the spread of alien plants and disease-carrying mosquitoes (Scott et al. 1986, Pratt 1994). Introduced birds are reservoirs for diseases, and potential competitors for food (Scott et al. 1986, Pratt 1994, Lepson and Freed 1997). Birds are negatively affected by competition with Japanese White-eye Zosterops japonicus (Freed and Cann 2009), and chewing lice are thought to be an additional threat (Freed et al. 2008a). Introduced rats, cats, Barn Owls Tyto alba and possibly small Indian mongooses Herpestes auropunctatus are predators (Lepson and Freed 1997). An outbreak of introduced yellow-jacket wasps coincided with a year of poor reproductive success, and introduced ants probably also compete for native arthropods at lower elevations (Lepson and Freed 1997). In addition to exacerbating the threat of introduced diseases, climate change is predicted to increase the geographic extent and intensity of habitat loss, invasive plants and non-native predators (Paxton et al. 2018).

Conservation Actions Underway
On Hawai`i, a large population is protected in Hakalau Forest National Wildlife Refuge and, to a lesser extent, in Ka`u Forest Reserve, Kulani Prison, Kilauea-Keauhou forests, Kona Forest National Wildlife Refuge and Pu`u Wa`awa`a State Wildlife Preserve (Lepson and Freed 1997, J. M. Scott in litt. 1999). Fencing, removal of feral pigs and cattle, and planting of koa seedlings and other native plants have all been carried out (USFWS 2006). Artificial nest-cavities and nest-boxes have been erected (Lepson and Freed 1997) and, in 1999 and 2000, c.10% of 60-70 boxes were used successfully (J. Lepson in litt. 2000). The species has been studied continuously at Hakalau Forest National Wildlife Refuge since 1987 (Freed et al. 2008b). Development of genetic tools to reduce transmission of avian malaria is ongoing. This includes transgenic or genetically modified mosquitoes that have reduced ability to transmit pathogens and also incompatible insect techniques, for example using a different strain of Wolbachia bacteria to produce males that cannot produce viable offspring (USFWS 2020, Miranda Paez et al. 2022).

Conservation Actions Proposed
Continue genetic research in disease immunity in Hawaiian honeycreepers (Paxton et al. 2018). Research potential limiting factors. Research response to habitat restoration (Lepson and Freed 1997). Expand studies of artificial nest cavities and evaluate their potential to facilitate range expansion and establishment of new populations (VanderWerf 2012). Determine feasibility of translocations to managed areas in their former range (VanderWerf 2012). Continue research in the fields of genomic technologies and genetically modified mosquitoes for disease control and their field application (USFWS 2020). Continue to monitor population trends to determine species response to management actions and effects of climate change (USFWS 2020).
Preserve unprotected native forests above the zone where mosquitoes occur (Ralph and Fancy 1994). Secure deforested and pasture lands on Hawai‘i at high elevations adjacent to protected refugia and manage these areas for forest growth to provide suitable habitat (USFWS 2020). Continue habitat management in areas where the species currently exists (USFWS 2020). Control rodents to reduce competition for nest-sites and to reduce predation of chicks and eggs from artificial boxes (Jacobi and Atkinson 1995). Expand the programme for fencing and control of feral ungulates in native forests. Implement a landscape-level mosquito control programme (Paxton et al. 2018). Consider establishing captive breeding programmes. 

Identification

10 cm. Small, finch-like bird whose crossed bill tips are not apparent in the field. Adult male brilliant red-orange with dusky wings and tail. Straw-yellow bill. Female dull greyish-green, darker above, with yellow-orange tinge to breast, no black in lores. Immature males begin like female and become gradually more orange as they mature. Similar spp. Hawaii Creeper Manucherthia mana resembles female, but has darker face and very different behaviour. Dull-plumaged Hawaii Amakihi Chlorodrepanis virens has curved bill, dark lores. Voice Song a slow, lackadaisical trill that changes pitch and speed. Call a distinctive cheedle-ee.

Acknowledgements

Text account compilers
Vine, J.

Contributors
Freed, L., Lepson, J. & Scott, J.M.

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Recommended citation
BirdLife International (2024) Species factsheet: Hawaii Akepa Loxops coccineus. Downloaded from https://datazone.birdlife.org/species/factsheet/hawaii-akepa-loxops-coccineus on 22/12/2024.
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 22/12/2024.