Hawaiian honeycreepers

(Drepanididae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Drepanidinae

Thumbnail description
Small to medium, compact, finch-like, often brilliantly and variously colored birds with a wide variation of bill shapes and sizes

Size
3.9–8.3 in (10–21 cm)

Number of genera, species
21 genera; 51 species, including 13 subfossil and 15 extinct historically

Habitat
Forest

Conservation status
Critically Endangered: 6 species; Endangered: 5 species; Vulnerable: 7 species; Near Threatened: 5 species

Distribution
Endemic to the Hawaiian Islands

Evolution and systematics

Hawaiian honeycreepers are a splendid living textbook and gazetteer of adaptive radiation, or the evolution of many species, with varied characteristics, from one.

Establishing the relationships among the many genera and species of honeycreepers is ongoing and far from settled. As of 2002, ornithologists consider all honeycreeper species to be monophyletic, i.e., sharing one common ancestral species, probably a cardueline finch species from North America, a small flock of which reached the Hawaiian Islands sometime between 3 and 5 million years ago. Although the Hawaiian honeycreepers are as of 2002 often listed taxonomically as subfamily Drepanidinae within the family Fringillidae, the finches, for the purposes of this account they are treated as a separate family—the Drepanididae.

Once established in Hawaii, the founder species evolved and radiated explosively, filling empty ecological niches and producing a fantastically varied toolbox of bill forms for dealing with virtually every sort of food. Researchers have found fossils of honeycreepers as old as 120,000 years. Fossil ages in Hawaii are limited by the nature of the islands, which are volcanic and relatively transient in geological time.

Physical characteristics

Hawaiian honeycreepers are small to medium-sized, compactly built, finchlike birds, their plumage colors varying widely from dull olive green to brilliant yellow, crimson, and multicolors. The tongue is tubular in most species, with a fringed tip adapted to nectar feeding. Bill shapes and sizes vary enormously, and correlate directly with the foods favored by particular species. Some species retain stubby, cone-shaped, finchlike bills for generalized feeding on insects, seeds, and fruits. Others favor heavier, parrotlike bills for cracking seeds and chopping into especially tough food sources. The various sickle-billed species use their long, thin, downcurved bills to draw nectar from the depths of tubular and bell-shaped flowers. The akepa developed a bill with a crossed lower tip, which it uses like pliers. The Lanai hookbill sported a parrotlike bill with a sizeable gap between the two mandibles, for a function that will probably remain unknown.

Subfossil species had even more outrageous versions of the simple finch bill. Two species of shovelbills (genus Vangulifer), had bills that were long and thin but with broad, rounded tips. Unique among honeycreepers, these may have fitted the species out for snagging insects on the wing. The gapers (genus Aidemedia) had bills with powerful muscles for opening the bill against pressure. This trait has a parallel with the meadowlark (Sturnella sp.), which uses a gaping bill to force open sod for reaching earthworms. The extinct King Kong finch (Chloridops regiskongi) had the largest known honey-creeper bill. A reporter used the name "King Kong" as an adjective to convey the massiveness of the bill, and the comparison worked its way into scientific nomenclature.

Nearly all honeycreepers give off a strong, musky odor, which persists even in museum specimens.

Distribution

Honeycreepers are found only on the Hawaiian Islands. As considered here, the Hawaiian Islands include the familiar

major islands, as well as a string of minor islets to the northwest of the main group, which includes Laysan Island, Nihoa Island, and the Pearl and Hermes Reef.

Habitat

Most honeycreepers are forest-dwellers. Exceptions include the Laysan finch (Psittirostra cantans) and Nihoa finch, which live on small, treeless islets. Although various species on the main islands originally lived throughout the lowlands as well as in the higher, mountainous areas, habitat loss and the proliferation of mosquitoes carrying avian disease now confines them mainly to mid-level and high tropical mesic (moist) forests and rainforests, 1,968 ft (600 m) above sea level and higher, most of them dominated by ohia trees (Metrosideros polymorpha). Some species prefer drier forests or a mix of dry, mesic, and rainforests. Many species depend on nectar from ohia flowers as a major or supplementary food source.

Behavior

The living honeycreeper species, despite their bewildering differences, share behavioral traits passed down from their finch-like ancestors.

All honeycreepers are diurnal. Individuals may be solitary foragers or forage in family groups, while some species show mixed-flock activity when foraging, especially when seeking out patches of ohia blooms, notably amakihis (Hemignathus spp.) and iiwis (Drepanis coccinea). Individuals of opposite sexes form strong pair bonds, and such pairings are monogamous and long-term for most species.

Honeycreepers produce a range of calls and songs as varied and distinct as the instruments of an orchestra, from ethereal music to coarse raspings. Calls and songs may vary even within a species. Some species stake out and defend nesting and feeding areas, other species tolerate intruders of their own or other species. Amakihis stake out breeding territories of 1–2.5 acres (0.4–1 ha), which they aggressively defend. The akohekohe (Palmeria dolei) is perhaps the scrappiest of all the honeycreepers in this regard.

Feeding ecology and diet

Honeycreepers eat almost anything edible, and run the entire gamut from generalist, omnivorous feeding, e.g., Laysan finches and amakihis, to specialization on a single plant species. Individual species tend to confine their diets to one or a few major sources. Foods include nectar of ohia (a primary food source for several species), insects, spiders, land snails, slugs, fruit, tree sap, seeds and seedpods, seabird eggs, and carrion. Species with long, curved bills poke them into flowers to reach nectar, while insect-grubbers pull or tear up epiphytic growth and bark to find arthropods. Species may pluck and eat fruit, break open seabird eggs, and cut or tear open seed pods. The po'o-uli (Melamprosops phaesoma) is unique among honeycreepers in preferring land snails as its main food, eating them shell and all. The Laysan and Nihoa finches have developed a taste for seabird eggs, which they peck or break open to get at the soupy innards.

Laysan finches have survived lean times by eating carrion of dead seabirds.

The finch-billed and parrot-billed honeycreepers can be roughly assumed under various genera: the Laysan and Nihoa finches; the palila (Loxioides); the Kona, Wahi, and King Kong grosbeaks (Chloridops); the greater and lesser koa finches (Rhodacanthis), the o'u (Psittirostra), the Lanai hookbill (Dysmorodrepanis); and the Maui parrotbill (Pseudonestor). Bills of these genera and species are short, strong, and finchlike or robust and parrotlike. They may generalize their diets like the Laysan finch, or specialize in getting at and eating tough foodstuffs like seedpods and hard seeds or tearing apart "structurally defended resources," such as arthropods hidden under tree bark or seeds in tough, fibrous pods. Females and young among the finch-bills and parrot-bills tend toward olive green or grayish green plumage, the males of some species add brighter shades of yellow, orange, and red to the basic olive or gray. The Maui parrotbill (Pseudonestor xanthophrys) uses its aptly named mouthpiece to rip into branches and stems; pluck and open fruit; and lift bark and lichen clumps to find, snag, and eat caterpillars and the larvae and pupae of beetles. The diet of the Kona grosbeak (Chloridops kona) was highly specialized, its main food source being the small, rock-hard seeds of the naio or bastard sandalwood tree (Myoporum sand-wicense). The bird used its massive, heavily muscle-powered bill to crack open the fruits.

Honeycreepers with long, narrow, downcurved bills are scattered among several genera: the curve-billed honeycreepers (Hemignathus), the sicklebills (Drepanis); and the alauahios (Paroreomyza). The bills become almost needlelike in some of these and can be half the length of the body, all for reaching nectar in the depths of ohia and other blossoms. Honey-creepers in the genus Hemignathus (amakihis, akialoas, nukupu'us, and akiapolaau) have a shorter lower mandible. Akiapolaau have a straight, thick lower mandible only half as long as the upper. This bird hammers audibly on tree bark with its lower mandible and plucks insects out of holes with the upper.

The amakihis, which are among the least specialized of the honeycreepers, take an wide food selection: caterpillars, plant lice, and spiders, which they uncover by probing leaves and twigs; nectar from ohia, lobelias, mamane, canna, and pritchardia palm; and non-native bananas and fuchsias.

Reproductive biology

Breeding takes place generally November through July, the males display to females, some species in groups resembling leks, and the sexes form strong, monogamous pair-bonds. Pairs build simple cup nests of twigs, lichens, and other plant materials on tree branches. As with all passerines, Drepanididae hatchlings are altricial, i.e., naked, blind, and helpless. The first young leave the nests anytime from the end of January through July and August. Only the female broods, while the male feeds the brooding female and both parents feed the chicks. The sexes of many honeycreeper species differ subtly or markedly in colors (sexual dichromatism), the males being more vividly and variously colored, the females tending to

more cryptic coloration, favoring olive-greens and grays, although in some species both sexes have relatively plain rainment. A few species show sexual variation in size (sexual dimorphism), while some species show no sexual variation in size or color.

Conservation status

Fifteen species of Drepanididae have become extinct within historical times, mostly from loss of habitat through deforestation and environmental degradation. By IUCN standards, seven living species are Critical, five are Endangered, and three are Vulnerable. Nevertheless, all species are threatened to various degrees by a combination of loss of habitat, the introduction of mosquito-borne diseases of Culex quinquefasciatus, especially avian malaria (Plasmodium spp.) and avian pox, along with competition from and predation by invasive species. The o'u, Oahu alauahio (Paroreomyza maculata), and Maui nukupuu (Hemignathus lucidus affinis) may be extinct, none having been seen for several years. At the very cliff-edge of extinction is the po'o-uli, of which only three individuals remain.

At the opposite end of the scale, the amakihis are the most widespread, populous, and successful honeycreepers; their total population, all species, is estimated at an impressive

870,000. The several subspecies were formerly found on all the major islands. The iiwi, fairly common on the major islands, has a total population estimated at 340,000.

Significance to humans

Ancient Hawaiians made brilliant royal cloaks, mostly yellow and crimson, from thousands, if not millions, of tiny feathers of honeycreepers and other endemic birds of Hawaii. The practice has long been discontinued, but the honey-creepers earn their keep by pollinating ohia and other native plants and keeping the insect populations in check. Besides rendering those ecosystem services, they have become dependable ecotourism magnets. Their main value may be educational, as a visible, instructional living example of adaptive radiation. Finally, as poignant visions of endangered life, honeycreepers have become rallying symbols for conservation.

Species accounts

List of Species

Akepa

Loxops coccineus

taxonomy

Loxops coccineus Gmelin, 1789.

other common names

French: Loxopse des Hawaï; German: Akepa; Spanish: Akepa.

physical characteristics

5 in (12.5 cm); 4–6 oz (10–12 g). Male mostly bright orange, female gray-green with a paler underside. Bill is distinctive feature; it has a lower tip bent to one side, as in the crossbills (Loxia spp).

distribution

Big Island of Hawaii. Extinct on Oahu, probably extinct on Molokai.

habitat

Old growth koa and ohia forest, wet and mesic, 3,610–6,890 ft (1,100–2,100 m) above sea level.

behavior

Lively and nimble forager. Male's call is high-pitched, descending trill.

feeding ecology and diet

Uses its unusual bill to pry apart scales of buds to reach tiny insects inside; caterpillars are main diet.

reproductive biology

Monogamous. Pairs form from July through September, start nest building in March, female lays eggs anytime from mid-March to late May, hatchlings fledge by end of June. Both parents

feed chicks, but only female builds the cuplike nest. Males undergo a long delay in attaining adult plumage. Second-year males have mostly gray-green coloration like females, and rarely try to breed. Third-year males are partially orange, and small numbers breed; the next year males have full orange plumage and full breeding capacity.

conservation status

Listed as endangered federally, by state, and by the IUCN.

significance to humans

None known.

Akikiki

Oreomystis bairdi

taxonomy

Oreomystis bairdi Stejneger, 1887.

other common names

English: Kauai creeper; French: Grimpeur de Kauai; German: Akikiki; Spanish: Akikiki.

physical characteristics

4–4.7 in (10–12 cm); 0.4–0.6 oz (11–17 g). Mostly medium gray with a white belly; short, pink bill; legs and feet are stout and strong.

distribution

Kauai.

habitat

Montane mesic and rainforest above 1,968 ft (600 m).

behavior

Lively and active, yet elusive and quiet, moves with a distinctive creeping motion over tree bark while foraging (thus the name "creeper"), reminiscent of nuthatches (family Sittidae); can climb along trunks and branches in any direction. Its unassuming call is the source of its name.

feeding ecology and diet

Feeds mainly on insects and their larvae, spiders, millipedes, and slugs; nectar and fruit only rarely. Tongue is short, non-tubular, and forked, efficient at snagging and seizing insects from tight niches, unlike the brush-tipped nectar-lapping tongues common among honeycreepers. Birds forage singly, in pairs, or in family groups of up to four individuals. May also form flocks of up to 12 individuals of same species or in mixed flocks with anianiau and akeke'e.

reproductive biology

Male and female build cup nest of bark and plant fiber for clutch of two eggs. Previous year's fledglings often help in raising their parents' next brood.

conservation status

Abundant, but confined to limited area in central Kauai. Listed as Critically Endangered by IUCN, and of special concern by the U.S. Fish and Wildlife Service (USFWS).

significance to humans

None known.

Akohekohe

Palmeria dolei

taxonomy

Palmeria dolei S. B. Wilson, 1891.

other common names

English: Crested honeycreeper; French: Palmérie huppée; German: Schopfkleidervogel; Spanish: Akojekoje.

physical characteristics

7 in (18 cm); 1 oz (29 g); largest living honeycreeper. Sexes are monochromatic. Unique appearance of black plumage splashed and streaked with brilliant orange-scarlet and silver. Prominent, bushy, whitish crest curves forward over the bill. Crest is often dusted with ohia pollen, thus may serve as a pollinating organ, as well as a display feature.

distribution

Eastern Maui.

habitat

Montane mesic and rainforest from 3,800–6,500 ft (1,158–1,981 m) above sea level.

behavior

Boisterous and aggressive, with a wide range of rough, throaty calls; native name is derived from one such call. Strong flyer, chases off other species and conspecifics from preferred feeding and nesting sites, even attacking with bill and wings.

feeding ecology and diet

Feeds mainly on ohia blossom nectar, but supplements the liquid diet with caterpillars, flies, and spiders.

reproductive biology

Monogamous, nesting from November to early June. Females lay two eggs, parents fledge one or both chicks. Females do incubation and brooding, males feed females and chicks.

conservation status

Listed as Endangered federally and by state, and as Vulnerable by the IUCN. However, the population is stable at 3,800, and the adult survival rate is 95%.

significance to humans

None known.

Anianiau

Viridonia parvus

taxonomy

Viridonia parvus Stejneger, 1887.

other common names

English: Lesser amakihi; French: Hémignathe anianiau; German: Anianiau; Spanish: Anianiau.

physical characteristics

4.5 in (11.4 cm); 0.32–0.35 oz (9–10 g). Smallest living bird species of Hawaii. Compact build, looks almost spherical when perching. Bill is small, thin, and slightly downturned. Male is bright yellow over most of body, with white rump and slightly darker wings; female duller.

distribution

Widespread in mountain forests of Kauai Island.

habitat

Variety of habitats, from dry valleys to rain-soaked Alakai area.

behavior

Lively and active, hops along branches while foraging, seldom or never descends to the ground. Bonded male and female pair will defend a small territory about the nest site, the tree itself, or larger surrounding area up to 25–30 ft (7.6–9 m) across. Males chase off conspecific interlopers, tolerate other species up to a critical distance from the nest. Females join in repelling intruders only if they come too close to the nest. Song is melodious, high-pitched trill rendered "weesee" or "weesity" in sets of four; call is musical, high-pitched "orps-seet."

feeding ecology and diet

Prefers to forage above 1,968 ft (600 m) but may range as low as 330 ft (100 m); sips nectar and gleans insects. Forage and feed mostly as individuals, also operate in bonded pairs, family groups, and flocks at favorite nectar sites. May also join in mixed foraging and feeding flocks with akeke'e (Loxops caeruleirostris) and akikiki (Oreomystis bairdi).

reproductive biology

Pairs build nests from February to late May, eggs laid between March and June; young fledge between early April and early July.

conservation status

Not threatened. Tolerates considerable habitat disturbance and maintains a stable population estimated at 24,000.

significance to humans

None known.

Apapane

Himatione sanguinea

taxonomy

Himatione sanguinea Gmelin, 1788.

other common names

French: Picchion cramoisi; German: Apapane; Spanish: Apapane.

physical characteristics

5.25 in (13.3 cm); 0.5–0.56 oz (14–16 g). Plumage bright crimson with black wings and tail, white undertail and abdomen; long, downcurved bill.

distribution

Not threatened. Most abundant honeycreeper species, also one of the most conspicuous. Common in forests over 3,300 ft (1,000 m) on Hawaii, Maui, Kauai, and Oahu, rare or extinct on Molokai and Lanai.

habitat

Forests over 3,300 ft (1,000 m).

behavior

Social, gather into sizeable flocks and range about forests in search of blooming ohia. Calls varied, include squeaks, whistles, raspings, clickings, and musical trillings. Blunt wing tips make a loud and distinctive noise in flight, probably for group cohesion.

feeding ecology and diet

Flocks are lively and obvious when feeding on nectar of flowering ohia trees and flying considerable distances between forest patches of seasonal blooms. Flocks can become as dense as 3,000 individuals per 0.4 sq mi (1 sq km) when ohias are blooming. Then groups fly about looking for patches of ohia trees in bloom, and descend to drink nectar and glean insects.

reproductive biology

Breed throughout year, mostly during February to June, coinciding with the seasonal availability of ohia nectar.

conservation status

Not threatened. However, apapane are primary carriers of avian malaria and avian pox, making them major vectors of these diseases, since they fly so extensively.

significance to humans

None known.

Greater koa finch

Psittirostra palmeri

taxonomy

Psittirostra palmeri/Rhodacanthis palmeri Rothschild, 1892.

other common names

French: Psittirostre de Palmer; German: Orangebrust-Koagimpel; Spanish: Koa Grande.

physical characteristics

9 in (23 cm); weight unknown; was largest known honey-creeper. Sexually dimorphic; male was brilliant scarlet-orange on head, neck, and breast, with lighter orange below, and olive brown with orange touches on back, wings, and tail; female was brownish olive, somewhat lighter below.

distribution

Confined areas on the Big Island (Hawaii). Neighboring species were the closely related lesser koa finch (Rhodocanthis flaviceps) and the Kona grosbeak.

habitat

Mesic, high-elevation forests.

behavior

Active and agile, compared to the lethargic Kona grosbeak. Had little or no fear of humans and would approach a person who imitated their call or song. Male song a whistled series of up to six notes, each successive note held longer; male call a series of two or three whistles, descending in pitch and each like a long "weeek." Female alarm call was a low, deep single note, difficult to locate.

feeding ecology and diet

Greater and lesser koa finches and the Kona grosbeak had powerful bills for dealing with tough foods. Koa finches cut open and ate green pods and seeds of their staple food the koa tree (Acacia koa), and had large stomachs for processing masses of vegetable matter.

reproductive biology

Not known.

conservation status

Greater and lesser koa finches, and the Kona grosbeak were extinct within 10 years after discovery in the 1890s. All three species had restricted ranges.

significance to humans

None known.

Lanai hookbill

Dysmorodrepanis munroi

taxonomy

Dysmorodrepanis munroi Perkins, 1919.

other common names

English: Ou, Lanai finch, akiapolaau; French: Psittirostre de Munro; German: Ou; Spanish: Akiapolaau.

physical characteristics

6 in (15 cm); weight unknown. Light gray tinged with green on upperparts and whitish below, light band on wing and light mark over eyes. Most distinctive feature was bill resembling pair of pliers or a paper punch, the upper mandible curving downward, the lower mandible curving upward, leaving a gap between the two. At first glance bill looked deformed, and was once interpreted as a deformity. Some ornithologists classified the one specimen as an aberrant female of the o'u, but extraction of skull in 1986 proved it to be a distinct species.

distribution

Endemic to Lanai, recorded from the southwestern side.

habitat

Dry, montane akoko (Euphorbia lorifolia) forest at 2,000 ft (610m) above sea level.

behavior

Voice described by George C. Munro as "a strange bird chirp." Monroe characterized the species as a quiet, retiring bird, easily overlooked.

feeding ecology and diet

Preferred food is unknown. Individual shot by Munro in 1913 had been feeding on fruit of the opuhe (Urera sandwichensis), Munro speculated it also fed on the akoko (Euphorbia lorifolia). Dissection of the stomach found native berries, but hooked bill and relatively weak jaw musculature suggest it may have fed mostly on land snails.

reproductive biology

Not known.

conservation status

Extinct. First seen alive February 22, 1913, when Munro collected a single specimen in the Kaiholena Valley of Lanai. Munro was the only person to see the species, so nearly everything known about it is in his book The Birds of Hawaii (1960). Only existing specimen (Munro's) is in Bishop Museum in Honolulu. After 1913, Munro saw the bird on March 16, 1916, in the Kaiholena Valley, and on August 12, 1918, at Waiakeakua. The 1918 sighting was the last, by that time most of the native akoko forest on Lanai had been replaced by pineapple plantations.

significance to humans

None known.

Laysan finch

Psittirostra cantans

taxonomy

Psittirostra cantans Wilson, 1890.

other common names

French: Psittirostre de Laysan; German: Laysangimpel; Spanish: Certiola de Laysan.

physical characteristics

6–6.5 in (15–18 cm). Bill large and parrotlike, tip of upper mandible forms slight downward hook. Adult males have bright yellow head, throat, and breast; lower back and rump grayish brown, abdomen whitish, gray collar around neck. Females less gaudy, dark streaks in yellowish crown, some streaking on flanks, gray collar, yellowish throat and breast, dark brown spots along back.

distribution

Laysan Island and Pearl and Hermes Reef, a coral atoll; both sites part of a long string of such islets northwest of main Hawaiian Islands. Shares both sites with nesting seabirds.

habitat

Laysan is a low-lying, sandy island about 1,000 acres (405 ha) in area; no trees, but abundant shrubbery and grasses. Pearl and Hermes Reef is a coral atoll containing several small islands.

behavior

Lively and gregarious; do not fear humans, will even eat food out of hands of observers.

feeding ecology and diet

Omnivorous. Feed on carrion, insects, seeds, roots, sprouts, soft parts of plants and seeds, and interiors of tern eggs, whose shells it punctures with its beak to reach the soupy innards.

reproductive biology

At beginning of the breeding season, males gather and display to females in groups resembling leks. As Laysan has no trees, finch secures cup-shaped nest of grass and twigs in clumps of grass or in small bushes.

conservation status

Listed as Endangered by the USFWS and the State of Hawaii, and as Vulnerable by the IUCN. Habitat is vulnerable to violent storms and the proliferation of alien species. Nearly became extinct in the 1920s. Population had declined to about 100 individuals in 1923, but diet of carrion and seabird eggs helped them to survive.

significance to humans

Significance lies in the successful efforts of wildlife biologists to preserve the species, and in the implications for the study of adaptive evolution. Biologists transferred 108 birds from Laysan to Pearl and Hermes Reef in 1967. In less than 30 years, the beaks shortened in accordance with their new food sources, demonstrating how quickly species can physically change in adapting to a local environment. About 350 birds survive at Pearl and Hermes.

Palila

Loxioides bailleui

taxonomy

Loxioides bailleui Oustalet, 1877.

other common names

French: Psittirostre palila; German: Palila; Spanish: Palila.

physical characteristics

6–6.5 in (15–16.5 cm); 2 oz (56 g). Fairly large, with large, parrotlike bill. Sexes show little variation in coloring, both have bright yellow crowns, faces and necks, gray backs, white bellies and flanks, and dark beaks; wings are gray edged with yellow. Male has a dark patch surrounding each eye, somewhat muted in the female.

distribution

Western slope of Mauna Kea on Big Island of Hawaii, 6,000– 8,000 ft (1,829–2,438 m) above sea level.

habitat

Cool, montane, mamane-niao forest.

behavior

Tall trees and extensive crown cover among mamane (Sophora chrysophylla) and naio (Myoporum sandwicense) forests, with a high proportion of native understory plants for foraging and nesting. Call is loud, clear "chee-clee-o."

feeding ecology and diet

Feeds mainly on green seed pods of mamane trees, also mamane flowers, buds, naio berries, and caterpillars.

reproductive biology

Breeding season March to September; female lays two eggs.

conservation status

Listed as Endangered federally and by the IUCN. The population is fairly large, with an upper estimate of 5,000, but within a restricted range. A complicating factor with palila is their site tenacity. Most palila translocated by wildlife biologists to other areas, even with adequate food sources, return to their original sites or die of stress.

significance to humans

None known.

Po'o-uli

Melamprosops phaeosoma

taxonomy

Melamprosops phaeosoma Casey Jacobi 1974.

other common names

English: Black-faced honeycreeper; French: Po-o-uli masqué; German: Mauigimpel; Spanish: Puli.

physical characteristics

5.5 in (15 cm); 0.9 oz (25.5 g). Differs from all other honey-creeper species in odor, tongue structure, and vocalizations,

and its color pattern is unique among all Hawaiian native birds. In 1992 some ornithologists proposed excluding the po'o-uli from the Drepanididae, but this was not carried, and as of 2002, the species was included. Main color brown, male's crown is gray merging into dark brown on nape, belly is buff washed with brown. Most striking and memorable feature is black mask offset by white throat. Has short, black, finchlike bill and long, pale legs. Female is similarly colored, but more cryptically.

distribution

Northeastern slope of Haleakala Crater on Maui.

habitat

Lives just below timberline in rainy (up to 550 in [14 m] a year), high-altitude, nearly impassable ohia forest draped in epiphytic mosses, lichens, and ferns.

behavior

Spend most of their time foraging in dense forests in small family groups. Seldom vocalize, main calls are single or repetitive "chit."

feeding ecology and diet

Hop along tree limbs, tearing apart epiphytes and loose bark with finchlike bills and gleaning leaves and bark in the sub-canopy and understory, searching for beetles, spiders, and other invertebrates, especially land snails. Only honeycreeper to prefer land snails as major dietary item.

reproductive biology

Breeds February to June; lays one or two eggs in a cup nest.

conservation status

Critically Endangered. As of 2001, only three individuals (two females and one male), are known. Invasive rats probably main agents of this near extinction.

significance to humans

A rallying symbol for conservation.

Resources

Books

Carlquist, Sherwin. Hawaii, A Natural History. New York: Natural History Press, American Museum of Natural History, 1992.

Denny, James. The Birds of Kauai Honolulu: University of Hawaii Press, 2001.

Hilton-Taylor, C., comp. 2000 IUCN Red List of Threatened Species. Species Survival Commission (SSC) Red List Programme. Cambridge, UK: IUCN 2000.

Poole, A., P. Stettenheim, and F. Gill, eds. Birds of North America: Life Histories for the 21st Century. (Monograph Series) Po'o-uli, no. 272; Akepa, no. 294; Apapane, no. 296; Maui Parrotbill, no. 311; Anianiau, no. 312; Iiwi, no. 327; Ou and Lanai Hookbill, no. 335–336; Amakihis, no. 360; Akohekohe, no. 400; Kona Grosbeak, Greater, and Lesser Koa-Finches, no. 424; Kakawahie and Oahu Alauahio, no. 503; Greater and Lesser Akialoa, no. 512; Akikiki, no. 552; Akiapala'au and Nukupuu, no. 600; Maui Alauahio, no. 681. Washington, DC: American Ornithologists Union, YEAR.

Pratt, H. Douglas, Phillip L. Bruner, and Delwyn G. Berrett. The Birds of Hawaii and the Tropical Pacific. Princeton, NJ: Princeton University Press, 1987.

Scott, J. M., S. Conant, and C. Van Riper III, eds. Evolution, Ecology, Conservation, and Management of Hawaiian Birds: A Vanishing Avifauna. Studies in Avian Biology 22. Camarillo, CA: Allen Press, Cooper Ornithological Society, 2001.

Stattersfield, Alison J., and David R. Capper, eds. Threatened Birds of the World: The Official Source for Birds on the IUCN Red List. Barcelona: Lynx Ediciones, 2001.

Periodicals

"Hawaii, Showcase of Evolution." Natural History 91, no. 12 (December 1982).

Olson, Storrs L., and Helen F. James. "Description of Thirty-Two New Species of Birds From the Hawaiian Islands; Parts I and II, Passeriformes." Ornithological Monographs 45&46, bound as one; American Ornithologists' Union, 1991.

Simon, Chris. "Hawaiian Evolutionary Biology: An Introduction;" Trends in Ecology and Evolution 2, no. 7 (July 1987): 175–178.

Simon, J. C., T. K. Pratt, K. E. Berlin, and J. R. Kowalsky. "Reproductive Ecology and Demography of the Akohekohe.;" Condor 103, no. 4:(Nov 2001): 736–745.

Organizations

The Bishop Museum. 1525 Bernice Street, Honolulu, HI 96817-0916 USA. Phone: (808) 847-3511. E-mail: museum@bishopmuseum.org Web site: <http://www.bishopmuseum.org>

Pacific Island Ecosystems Research Center. 3190 Maile Way, St. John Hall, Room 408, Honolulu, HI 96822 USA. Phone: (808) 956-5691. Fax: (808) 956-5687. E-mail: Bill Steiner@usgs.gov Web site: <http://biology.usgs.gov/pierc/piercwebsite.htm>

Other

Payne, Robert B. "Bird Families of the World." University of Michigan Museum of Zoology, Bird Division. 12 Jan. 2000 (16 Mar. 2002). <http://www.ummz.lsa.umich.edu/birds/birddivresources/families.html.>.

Pratt, Thane. "Birds of Hawaii." Pacific Island Ecosystems Research Center. 18 June 2001 (16 Mar. 2002). <http://biology.usgs.gov/pierc/PLPrattTPage.htm.>.

Kevin F. Fitzgerald, BS