Kauai amakihi  (Hemignathus kauaiensis)

Classified as Vulnerable (VU) on the IUCN Red List (1).

The Kauai amakihi (Hemignathus kauaiensis) is a small honeycreeper endemic to Kaua’i in the Hawaiian Islands (2). It can be distinguished from similar bird species by its distinctive curved bill (3).

The male Kauai amakihi has a bright olive-yellow head and breast, and is darker green on the wings and back, with grey undertail coverts. The female and juvenile have the same patterning, but are not as brightly coloured (2).

The Kauai amakihi has a much longer bill than other members of the Hemignathus genus (2) and the bill is browner than other amakihis (3). Its bill is palest on the lower mandible towards the head and becomes darker towards the tip (3).

The main song of the Kauai amakihi is a vigorous trill, but it also produces short ‘chirps’ and ‘mewing’ (2) (3).

The Kauai amakihi is found in only a few regions on Kaua’i Island in the Hawaiian Islands. It occurs in the Alaka’I Wilderness Preserve and Koke’e State Park, and there is also an isolated population in the Makaleha Mountains (2).

Usually found among the treetops in forests, the Kauai amakihi occurs at elevations above 600 metres. It is most common in western koa-‘ohi’a forest, but it is not known whether koa (genus Acacia) itself or the prevalence of introduced banana poka (Passiflora tarminiana) attracts the Kauai amakihi to this area (2).

The Kauai amakihi uses its long, powerful bill to excavate arthropods from under the bark of trees but it will also glean insects found on tree trunks and branches. Being omnivorous, the Kauai amakihi also feeds on nectar from species such as Kaua’i koli’i, ‘ohi’a and kanawao, as well as from introduced species such as the banana poka and Methley plum (Prunus salicina). The Kauai amakihi can be found foraging among mixed-species flocks (3).

The breeding season for the Kauai amakihi is from March to July. In March and April, the male Kauai amakihi performs a courtship display, whereby it will sing, chase, and dance for a female. The male will also provide food for the female before and during nest building, as well as throughout incubation (3).

The nest is constructed by both sexes of the Kauai amakihi, and is formed using materials such as twigs, roots and moss, with a lining of shredded bark and grasses. The nest is typically found in ‘ohi’a approximately five metres above the ground. A couple of days after the nest is completed, the female Kauai amakihi lays a clutch of one to four white, brown-speckled eggs (3).

Following a 14 day incubation period by the female Kauai amakihi, the helpless nestlings hatch. The nestlings’ eyes remain closed for four days and their feathers begin to develop after seven days. The male and female Kauai amakihi feed the young and take faecal sacs from the nest, but usually only the female broods the young during the night. The Kauai amakihi chicks fledge from 17 to 20 days after hatching (3).

Due to its small range, the Kauai amakihi is extremely susceptible to habitat degradation. Many lowland forests on Kaua’i have been removed due to human development, which has reduced its breeding habitat. Introduced predators such as cats and rodents also threaten this species, and non-native plant species and ungulates are degrading its forest habitat (2).

A significant threat to the Kauai amakihi also comes from avian malaria, spread by mosquitoes which are only active at elevations below 1,200 metres. Studies have shown this disease to be fatal to 65 percent of Kauai amakihis infected by a single bite (5).

Hurricanes and other natural disasters which may damage forest canopy plants are also a concern, as the Kauai amakihi is highly dependent on these species (2).

The Kauai amakihi is partially protected as its range includes two nature reserves on Kaua’i: the Alaka’i Wilderness Preserve and the Koke’e State Park. Protected ungulate-free areas are being established using fencing in the Alaka’i Wilderness Preserve; however, there are no known conservation measures currently in place specifically for the Kauai amakihi (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more about the Kauai amakihi:

• BirdLife International - Kauai amakihi:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=8906