Wildlife & Habitat

Learning From the Past to Protect the Future

Much of Hawai‘i’s native lowland habitat was degraded following the Polynesians’ arrival over a thousand years ago. In the late 1700's, cattle, goats, and European pigs were released into the forests, and hundreds of additional alien plants, animals, and insects have subsequently been introduced. Most lowland plants seen today like the orchid, ginger, and plumeria are aliens or nonnative. Mosquitoes, wasps, mongooses, cats, and rats are other examples of animal introductions that have had detrimental impacts on Hawaiian habitat and native species.

Grazing pressure by cattle and pigs has resulted in the replacement of Hawaiian plants by more competitive alien grasses and shrubs within the upper portions of Hakalau Forest. Below this pasture area, the native tree canopy is still intact, but the native understory has been replaced by alien grasses, blackberry, banana poka, and English holly. The replacement process may have been accelerated by efforts to create more pasture land through bulldozing and burning, and by logging mature koa and ‘ōhi‘a trees for timber and fence posts.

Habitat loss is only one of the factors responsible for diminishing populations of native birds. Diseases carried by alien birds and spread by introduced mosquitoes; competition from alien birds and insects for food and space; and the introduction of predators such as rats, cats, and mongooses are also responsible for population declines.

Common Native Birds at Hakalau Forest NWR

Hawaiian Honeycreepers

	‘I‘iwi  - This nectar feeding member of the honeycreeper family, with its brilliant scarlet body plumage and black wings and tail, abounds in the forest canopy where ‘ōhi‘a lehua blossoms are plentiful. The ‘i‘iwi's long, down curved, orange bill is specialized for sipping nectar from tubular flowers. The ‘i‘iwi’s "squeaky hinge” call can be heard throughout the forest when the birds are present.
‘I‘iwi - Photo credit © Jack Jeffrey
	‘Apapane - This honeycreeper has a crimson red body with a white abdomen and white feathers under the tail. The wings, tail, and legs are black. The bill is black and slightly curved. ‘Apapane forage actively in the forest canopy for nectar and insects. They favor ‘ōhi‘a trees, but also visit flowering koa.
‘Apapane - Photo credit © Jack Jeffrey
	‘Amakihi - The ‘amakihi feeds mostly on insects but frequently takes nectar from flowers. The male is yellow with a thin black mask and a moderately long, black, down curved bill. Female and young ‘amakihi are olive green with a paler mask. This species commonly forages from low to upper levels of the forest canopy.
‘Amakihi - Photo credit © Jack Jeffrey
	‘Akiapōlā‘au - The rare and endangered ‘akiapōlā‘au occurs in only a few areas of upper elevation koa/‘ōhi‘a forest on the Big Island. Skill and luck are required to find this bird anywhere within its range. The ‘akiapōlā‘au feeds on insects and caterpillars living in the wood and under the bark of koa trees. Its bill is one of the most unusual in the honeycreeper family. The lower bill is short, straight, and stout. With mouth agape, it is used to chisel (woodpecker style) holes in tree wood. The upper bill is long, curved, and slender; and is used to probe, pierce, and pull prey from the hole. The male is brilliant yellow with a black mask; the female is dull green with a less distinctive mask and a slightly shorter bill.
‘Akiapōlā‘au - Photo credit © Jack Jeffrey
	Hawai‘i ‘Ākepa - The ‘ākepa is an insect-eating, endangered honeycreeper with a short, straight bill. The male is blaze orange and the female is gray-green with tinges of yellow or orange on the breast. Using its crossed bill to open leaf buds, the ‘ākepa feeds on insects found among the leaves and flowers at the very top of ‘ōhi‘a trees. It is the only Hawaiian honeycreeper that always nests in tree cavities.
Hawai‘i ‘ākepa - Photo credit © Jack Jeffrey
	Hawai‘i Creeper - Both male and female endangered Hawai‘i creepers are olive green and have a short, straight gray bill and black mask. The chin and chest are lighter than the rest of the bird. Creepers are often found in family groups or in loose flocks of mixed species and call softly to one another while flitting from tree to tree. Creeping up and down koa and ‘ōhi‘a tree trunks and along the underside of larger branches, this bird feeds on insects living under the loose bark.
Hawai‘i creeper - Photo credit © Jack Jeffrey/USFWS

Other Native Forest Birds

‘Io - The largest endangered forest bird in Hawaii is the ‘io (Hawaiian hawk). It is frequently seen soaring high above the tree canopy in search of birds, large insects, mice and rats. The ‘io occurs in two color phases. Light-phase birds are dark brown above and pale below with dark streaking. Dark-phase birds are all brown. While color does not indicate age or sex, younger birds tend to have paler heads. The female is slightly larger than the male. The ‘io population has increased during recent years. Rarely seen in the 1960s and 1970s, ‘io are now frequently observed from the coast to the tree line on mountain slopes. Many Hawaiian families believe the ‘io to be their guardian spirit (‘aumakua).
	‘Io - Photo credit © Jack Jeffrey
‘Elepaio - The ‘elepaio is a small brown and white flycatcher. This curious bird actively flits from tree to tree in the understory, picking insects from the vegetation and catching them in the air. It can be heard calling its own name "‘e-le-pai-o" in its squeaky “rubber ducky”-like voice.
	‘Elepaio - Photo credit © Jack Jeffrey
‘Ōma‘ō - The ‘ōma‘ō (Hawaiian thrush) is found throughout the forested areas of the refuge. This robin-sized bird has a dark brown back and a light gray breast. Although common on the refuge, its subdued coloration makes it difficult to spot, but loud “grrrack” and “whistled trill” calls can be heard for long distances in the forest. The ‘ōma‘ō feeds on native fruits and berries.
	‘Ōma‘ō - Photo credit © Jack Jeffrey

Other Endangered Birds at Hakalau

Additional endangered birds have been sighted at Hakalau Forest. The ‘ō‘ū, a finch-billed honeycreeper with a yellow head, was last sighted in 1977. This extremely rare bird feeds on forest and aids in the dispersal of native seeds.

	The nēnē (Hawaiian goose), the State bird of Hawai‘i, was reintroduced to the refuge in 1996. It breeds from November to March at the refuge and is regularly seen in the upper elevation grasslands where it feeds on grasses, seeds and berries. The refuge nēnē population is approximately 200 birds.
Nēnē - Photo credit USFWS

The koloa (Hawaiian duck) is sometimes seen on stockponds and puddles at the refuge.

A single ‘alae ke‘oke‘o (Hawaiian coot) was observed regularly on a stockpond at Hakalau Forest NWR from 1990 through 2000.

The pueo (Hawaiian short-eared owl) is commonly seen at the refuge during daylight hours, soaring over open areas in search of rodents, insects, and small birds.
	Pueo - Photo credit © Jack Jeffrey

Hawai‘i’s only native terrestrial mammal

	The endangered ‘ōpe‘a pe‘a (Hawaiian hoary bat) is a common resident at the refuge but is seldom seen because its nocturnal behavior makes it difficult to see. The bat is an insect feeder and forages in forest openings searching for flying insects which it takes in flight.
‘Ōpe‘a pe‘a - Photo credit © Jack Jeffrey