Forest and Mountain Birds of the Hawaiian Islands

Forest and Mountain Birds

of the Hawaiian Islands

He ali‘i ka manu.

A bird is a chief.

A bird flies and perches higher than any human.

(Pukui: 534-63)

Forestand Mountain Birds of the Hawaiian Islands

Hawaiian Owl (Pueo)

Hawaiian Hawk (‘Io)

Hawaiian Crow (‘Alalā)

Hawaiian Goose (Nēnē)

Honeycreepers and Honeyeaters

(and other small forest birds)

Original Colonizing Species

Populations and Extinctions

Hawaiian Featherwork

Hawaiian Honeycreepers;

Evolutionary Processes / Adaptive Radiation

‘Akialoa and ‘I‘iwi;

The ‘Elepaio

The Puaiohi—Captive Breeding

Threats to Endemic Forest Birds

The Hawaiian Owl (Asio flammeus sandwichensis)

Hawaiian Name: Pueo

Also called: Short-Eared owl.


Status: Species of Concern (federal listing: actually a subspecies). Endangered on O‘ahu (state listing).

Considered by Hawaiians to be an ‘aumakua, or guardian spirit, the pueo is about 15 inches (38 cm) long with yellow eyes, a round facial disc, a black bill, and brown and white feathers. The pueo is an endemic Hawaiian subspecies of the short-eared owl. The pueo’s call is a repeated "tchak" sound, though the bird is usually silent.

The pueo’s habitat includes lowland pastures and fields as well as higher forest areas at elevations up to 8,000 feet (2,438 m). Pueo often hunt over grassland areas, mostly at dawn and dusk but also during daylight hours.

The pueo eats insects and rodents (e.g., mice) as well as other birds including both native and introduced species. The pueo may also prey upon the native ‘ōpe‘ape‘a (Lasiurus cinereus semotus, Hawaiian hoary bat).

Pueo often hover briefly over their prey before diving down for the attack. Unlike most other owls, the pueo often soars high in the sky, and is diurnal (active during the day).

[Illustration: Pueo]

Malu ke kula, ‘a‘ohe ke‘u pueo.

The plain is quiet; not even the hoot of an owl is heard.

All is at peace.

(Pukui: 2130-232)

There is very little research and documentation of pueo nesting behavior. Pueos are thought to nest throughout the year in the Hawaiian Islands, and the peak breeding months are March through June, the same as most other Hawaiian forest bird species.

During courtship, the pueo gives a series of low hoots and claps its wings. The owl lays usually from three to six white eggs in a nest built on the ground in a grassy area. Nests are built on the ground, but rarely seen.

One researcher discovered a pueo nest of six eggs in a depression in tall grass on the downhill side of a dead snag of māmane (Sophora chrysophylla).

Pueo Population

No pueo fossils have been found dating to the time before the first Polynesian settlers arrived in the Hawaiian Islands. Pueos need open grassland habitats, and researchers theorize that the pueo may not have become established on the Hawaiian Islands until after the Polynesian settlers arrived and altered the landscape, increasing the amount of grassland and creating other suitable habitat that then made pueo colonization attempts successful.

The pueo is found on all of the main Hawaiian Islands, with the largest populations found on Maui, Kaua‘i and the island of Hawai‘i. The O‘ahu pueo population is listed as endangered by the State of Hawai‘i. The pueo’s roundish facial area helps to distinguish it from the non-native barn owl, which is also found in the Hawaiian Islands.

The legend of Pu‘upueo (“Owl hill”) in Mānoa, Honolulu tells of a beautiful woman named Kahala-o-Puna. All three times that Kahala-o-Puna was killed by her jealous husband she was resuscitated by the owl that lived on the hill, which is now known as Pu‘upueo.

[Photograph: Pueo]


The Hawaiian Hawk (Buteo solitarius)

Hawaiian Name: ‘Io


Status: Endangered Species. Found on island of Hawai‘i Island only.

A sacred hawk in Hawaiian mythology, the ‘io is about 17 inches (43 cm) long, with the female on average a little bigger than the male. “Dark-phase” birds are dark brown above and below, while “light-phase” birds are dark on top but lighter colored below with dark streaks.

The immature ‘io has a light-colored head that darkens as the bird becomes an adult. The legs also go from a green to a more yellowish color.

An Hawaiian proverb from ancient times states: “He ‘io au, he manu i ka lewa lani.” (I am an ‘io, the bird that soars in the heavenly space.”), which is explained to mean, “A boast. The highest chiefs were often called ‘io (hawk), king of the Hawaiian birds.”[i]

[Illustration: ‘Io]

In air, the ‘io soars gracefully, searching for insects, rodents, and other birds (including young game birds). The ‘io is also a natural predator of the native ‘alalā (Asio flammeus sandwichensis, the native Hawaiian crow) and the native ‘ōpe‘ape‘a (Lasiurus cinereus semotus, Hawaiian hoary bat). The ‘io is often are seen soaring high in the air in large circles.

A vocal hawk the ‘io makes the most sound during the breeding season. The ‘io’s vocalization is a high-pitched “kee-oh” sound. Little is known about breeding and nesting behavior, though most nesting is through to occur from May to October.

The hawk builds a nest in a tree using twigs and leaves, and then lays usually from one to three light blue eggs. Both parents participate in the feeding and aggressive protection of the fledglings.

‘Io Population

The ‘io was listed as endangered in 1967, and in 1982 the ‘io population was estimated to be between 1,400 and 2,500 hawks. The ‘io population likely remains near that number today.

Fortunately, the ‘io population is spread through a wide range of habitats and elevations, making it less vulnerable to sudden declines in population. On Hawai‘i Island the hawk may be seen over the slopes of Mauna Kea and Kohala Mountains as well as Mauna Loa.

The ‘Io in Ancient Hawai‘i

‘Iolani was a sacred hawk of Hawaiian mythology, and also one of the names of King Kamehameha IV (Alexander Liholiho ‘Iolani). ‘Iolani means “Hawk of heaven,” or “Royal hawk,” and the flight of the ‘io was believed to be a sign of royalty.

In December of 1879, the cornerstone was laid for ‘Iolani Palace in midtown Honolulu. A project of King Kalākaua [David La‘amea Kalākaua], ‘Iolani Palace was built on the site of the earlier royal palace, called Hale Ali‘i.

Hale Ali‘i was built in 1845 for King Kamehameha III (Kauikeaouli), and named ‘Iolani in 1863 at the request of King Kamehameha V (Lot Kapuāiwa Kamehameha) who wanted a name chosen to honor his deceased brother, the former King Kamehameha IV (Alexander Liholiho ‘Iolani).

‘Iolani Palace was the seat of the Hawaiian monarchy for King Kalākaua and later for Queen Lili‘uokalani [Lydia Kamaka‘eha Pākī-Dominis Lili‘uokalani]. (See O‘ahu, Chapter 2; Chapter 11, Timeline: 1895, Jan. 6; 1879, December 31.)

[Photograph: ‘Io]
The Hawaiian Crow (Corvus hawaiiensis)

Hawaiian Name: ‘Alalā


Status: Endangered Species. Found on Hawai‘i Island only, and in propagation.

The ‘alalā is about 19 inches (48 cm) long, with a black beak and legs, and dark brown and black feathers. The Hawaiian crow’s color is a duller black than its North American relatives. The crow also has tinges of brown on its wings, and hair-like throat feathers that are stiff and grayish.

The ‘alalā often makes a “cawak” sound as well as other loud vocalizations, especially during the breeding season. The word ‘alalā comes from ala (to rise up) and lā (the sun), and refers to the crow’s habit of filling the forest with its raucous sounds early in the morning.

[Illustration: ‘Alalā]

He ‘alalā, he manu leo nui.

It is the crow, a loud-voiced bird.

Said of a person who talks too loud.

(Pukui: 527-62)


The ‘alalā is an omnivorous bird that feeds on fruit and nectar as well as insects and carrion. Its diet has changed due to changes in its habitat, but the original populations of ‘alalā fed primarily on native berries, such as ‘ōhelo (Vaccinium reticulatum) as well as the fruit and flower of the ‘ie‘ie vine (Freycinetia arborea). ‘Alalā may also eat mice.

In spring (from April to June) the ‘alalā builds a nest using twigs and grasses, and breeding occurs from March to July. The ‘alalā lays up to five greenish-blue eggs, though it’s likely only two will survive. Fledglings may remain with their parents for up to one year.

‘Alalā Population

The ‘io (Buteo solitarius, Hawaiian hawk) is a natural predator of the ‘alalā, but this was not a significant factor in the precipitous decline of the species over the last century, though it has been a factor more recently (see below). The primary causes of the ‘alalā’s historic population decline include the intentional killing of the birds by humans as well as loss of habitat.

Farmers began killing the ‘alalā in the 1890s because the birds would get into the poultry yards and feed pens. The ‘alalā population began seriously declining in the mid-1900s due to avian diseases (e.g., avian malaria, avian pox), predation by feral mammals, shootings by farmers, and cattle grazing on land that had previously been ‘alalā habitat. Another avian disease affecting ‘alalā is taxoplasma, which is transported to the birds through the droppings of feral cats.

In 1967, the ‘alalā was listed as a federally endangered species. In 1976, a captive rearing program at Pōhakuloa on the island of Hawai‘i attempted to raise ‘alalā, but the effort was unsuccessful. By 1978 less than 100 ‘alalā were left.

In 1981, when the wild ‘alalā population was estimated at somewhere between 30 and 150 birds, unsuccessful attempts were made to breed ‘alalā at Pōhakuloa on Hawai‘i Island. Then three ‘alalā eggs from captive ‘alalā nests were artificially incubated and hatched at the Honolulu Zoo.

In 1987, the ‘alalā was on the edge of extinction with just one bird in North Kona and several more in central Kona. A 1991 National Audubon Society lawsuit against the United States Fish & Wildlife Service and McCandless Ranch initiated the capture of some of the last wild ‘alalā as part of a recovery plan.

In 1992, the wild population of ‘alalā was believed to be just 12 birds as work to save the bird species from extinction was undertaken by the Peregrine Fund, under contract by the U. S. Fish & Wildlife Service.

Eggs were taken from Kealia Ranch, Kai Malino Ranch, and McCandless Ranch, and ‘alalā chicks were raised at captive propagation facilities at Olinda on Maui (Maui Bird Conservation Center) and at Volcano on Hawai‘i Island (Keauhou Bird Conservation Center). Both facilities are operated by the Zoological Society of San Diego.

In 1993, seven ‘alalā were born, five of which were released into the wild in their native habitat on the island of Hawai‘i. In 1995, seven more chicks were released on Hawai‘i Island. By 1997, four more ‘alalā had been released into the wild, and the number of ‘alalā in captivity reached 40.

In 1997, when the wild ‘alalā population was estimated to be just 15 birds, the species suffered a severe setback when five captive-released ‘alalā were killed by ‘io (Buteo solitarius, Hawaiian hawks). It is possible that some of the ‘alalā preyed upon by ‘io had been weakened by taxoplasma.

In response to the multiple ‘alalā deaths, the U. S. Fish & Wildlife Service began trapping the ‘io (also an endangered species), and relocating the hawks to Volcano, but they quickly returned to the McCandless Ranch in South Kona.

The Wildlife Service then caught ten ‘alalā and shipped them to zoos on the United States Mainland as part of a captive breeding program. Five of these ‘alalā later died.

By 1999, releases of captive-bred ‘alalā were halted due to the high death rate of released birds. As of the year 2000, there were 33 ‘alalā, with 30 in captivity.

By the beginning of 2004, there were 40 ‘alalā in captivity. No ‘alalā had been seen in the wild since June of 2002, when one bird was sited at Kealia Ranch in South Kona, though several persons claimed they had heard ‘alalā. If the species is re-established in the wild, it is likely that some “cultural” knowledge among the species will be lost, as the young birds will have not have been raised by their parents in the wild, when much of the generational information is typically learned.

The primary remaining habitat for ‘alalā is found in south Kona on the island of Hawai‘i. This mixed forest of koa (Acacia koa) and ‘ōhi‘a lehua (Metrosideros species) is on the 5,300-acre (2,145-ha) Kai Malino Ranch and another 1,258 acres (509 ha) nearby.

This unique leeward rainforest also supports other endangered bird species, including the ‘akia pōlā‘au (Hemignathus munroi), the Hawai‘i creeper (Oreomystis mana), and the ‘io (Buteo solitarius, Hawaiian hawk). Another native species seen in the region is the ‘ōpe‘ape‘a (Lasiurus cinereus semotus, Hawaiian hoary bat).

Continued threats to the ‘alalā include loss of habitat due to the logging of koa, which is highly valued for fine furniture and other items. (See Koa in Native Plants and Ferns of the Hawaiian Islands, Chapter 8.) Another species of crow once lived on O‘ahu, and a separate species lived on Maui, but both are now extinct. Hope remains that the extremely endangered ‘alalā will not also suffer that fate.

[Photograph: ‘Alalā]


Nēnē—The Hawaiian Goose (Branta sandvicensis)


Status: Endangered Species. Found on Maui, Kaua‘i, and Hawai‘i Island. Recent releases on Moloka‘i (see below).

Many thousands of years ago, some Canadian geese were blown off course or perhaps caught in a storm, and ended up in the Hawaiian Islands. Today their descendents have evolved into a unique Hawaiian bird known as the nēnē. This endemic goose species is now Hawai‘i’s official state bird.

[Illustration: Nēnē]

“Unele! Unele!” wahi a ka nēnē.

“Honk! Honk!” says the goose.

A play on nele (a lack, poverty), this saying implies a going without,

a lack of success, chagrin, and so forth.

(Pukui: 2878-314)

The nēnē is about 2 feet (61 cm) long, which is a typical size for a goose. The nēnē’s head, face, and the back of its neck (the nape) are black, and the cheeks and the sides of the neck are a light tan color, with a buffy striped pattern (distinct horizontal bands). The nēnē’s lower body has this same light brown color and is striped, but the top of the body is a darker gray or brown.

The nēnē’s bill is black, as are its legs and feet. The webbing between the toes on the nēnē’s feet is much reduced compared to the fuller webbing on the feet of its ancestor, the Canadian goose. This adaptation is better for walking on high, dry lava flows and other habitats frequented by the nēnē.

When nēnē fly they make a “ney ney” sound, but on the ground nēnē sometimes make a different noise, slightly similar to a cow’s moo. Nēnē aren’t very shy, and sometimes even approach humans.

Feeding and Habitat

Nēnē eat grasses, seeds, buds, flowers, berries and leaves, and are especially fond of native plants such as berries of naupaka (Scaevola species), ‘ōhelo (Vaccinium species), kūkaenēnē (Coprosma ernodeoides), pūkiawe (Styphelia tameiameiae) and ‘ulei (Osteomeles anthyllidifolia, Hawaiian hawthorn). Nēnē prefer high, dry areas like old lava flows as well as wetlands and forest uplands.


Researchers previously believed that nēnē mate for life, though a nēnē at Maui’s Haleakalā National Park was seen to have three different mates in just a several month period. The first had been the nēnē’s mate for about ten years when another male chased it away. A few months later another male displaced that mate.

In ancient Hawaiian lore, the promiscuity of the nēnē is implied in several native Hawaiian proverbs or sayings that link the birds’ amorous behavior to the behavior of certain men.

The nēnē builds its nest on the ground and lines it with feathers. This ground nesting is one reason nēnē became so endangered (ground predators include mongooses, pigs, rats, and domestic animals).

By the age of two, nēnē begin laying eggs. They nest between October and March, and one nēnē may lay from two to five (usually four or five) creamy, white eggs.

They sit on the eggs for about 30 days while the eggs incubate. Sometimes the mother leaves the nest during this time and when she does, she covers the eggs with the downy feathers that are part of the nest lining.

During nesting, the adults go through a four to six week process called molting, at which time the adult birds cannot fly. The infant chick is able to run around just as soon as the chick’s downy feathers dry. The parents provide food for the baby until the hatchling is about 10 to 12 weeks old, when the gosling learns to fly.

Nēnē Population

Genetic research has revealed that there was a marked decline in the population of nēnē (and other bird species) between about A.D. 1100 A.D. and A.D. 1750. These population declines (and in some case extinctions) in native Hawaiian bird species in the centuries before Western contact with the Hawaiian Islands is generally attributed to Hawaiians hunting the birds for food.

Fossil records show that nēnē were once common at lower elevations on Kaua‘i, but then became extinct by the time Captain Cook arrived in 1778. Apparently the early Polynesian settlers had eliminated the nēnē on Kaua‘i, but the birds survived on other Hawaiian Islands.

There were an estimated 25,000 nēnē living on the island of Hawai‘i in 1778. Predatory animals, habitat destruction, hunting, and egg collecting eventually decimated the nēnē populations of all the Hawaiian Islands.

The Maui nēnē population became extinct around 1890. By 1951, there were only about 30 nēnē left in the wild as well as some captive nēnē in European and American zoos. Nēnē were federally listed as endangered in 1967.

Beginning in 1949, scientists began raising nēnē in captivity, including more than 1,600 birds raised at Pōhakuloa on Hawai‘i Island. Almost all of these birds were released in Maui’s Haleakalā Crater and on Hawai‘i Island with the goal of re-establishing natural nēnē populations.

Beginning in 1951, nēnē were also raised at England’s Slimbridge Wildfowl Trust. Two hundred of these nēnē were released on Maui in the 1960s (at least two were still alive in 1990).

In all, more than 2,000 nēnē were raised in captivity between 1960 and 1990 and released on three of the Hawaiian Islands (Kaua‘i, Maui, and Hawai‘i Island). More than 80% of these nēnē were raised at the Endangered Species Facility in Olinda, Maui.

Nēnē restoration efforts have been a great success. The wild nēnē population increased to more than 1,300 birds statewide in 2004, though nēnē are still considered endangered. It’s estimated that the population atop Maui’s Haleakalā Volcano is about 250 nēnē, with about 60 more of the birds living in West Maui.

In addition to the wild nēnē population in the Hawaiian Islands, there are also up to 2,000 nēnē in captivity in U.S. and European collections and zoos.

The island of Kaua‘i is now considered the ideal place for the nēnē because there are no mongooses on Kaua‘i, as there are on the other main Hawaiian Islands.

On Kaua‘i the population of nēnē has rapidly grown, and they are seen in various low elevation habitats (e.g., lower Hanalei Valley) as well as higher elevations (e.g., Kōke‘e State Park). On other Hawaiian Islands, however, nēnē populations are generally restricted to higher elevations.

Nēnē were first re-introduced to Moloka‘i in the early 1960s, with numerous bird releases occurring until 1978. In December of 2001, ten nēnē were released at Pu‘u O Hōkū Ranch in eastern Moloka‘i in the Cape Hālawa region.

The released birds were reared as part of a captive flock at the state’s Maui Bird Conservation Center at Olinda, Maui, which is operated by the Zoological Society of San Diego using funds provided by the federal government and the State of Hawai‘i. In 1995, a nēnē reintroduction program began at Hana‘ula in West Maui.

At least another 55 nēnē have been released on Moloka‘i, including eight nēnē released at Pu‘u O Hōkū Ranch in June of 2003. The nēnē releases at Pu‘u O Hōkū occurred as part of the State of Hawai‘i’s first “safe harbor” agreement in which the private landowner, in turn for providing habitat for the endangered birds, is given assurances that no further restrictions will be placed upon the land due to the endangered species living there.

In the last decade nēnē have also been released in the West Maui Mountains and on Kaua‘i.

The Nēnē Count

For more than a decade an annual nēnē count has been conducted at Haleakalā National Park, where about 250 of the birds now exist. The survey is held in August, the time of year when single nēnē adults and family groups of nēnē flock before breeding season.

Various agencies participate in the nēnē count, including the U.S. Fish and Wildlife Service, the Nature Conservancy, the University of Hawai‘i and others.

[Photograph: Nēnē]


Honeycreepers and Honeyeaters

and other small forest birds

[Illustration: Beaks of different honeycreepers]

The songs of small forest birds of the Hawaiian Islands echo through the high tropical forests. Some of these birds have long, thin beaks while others have short stout beaks.

Some have beaks designed for probing bark and grasping insects, while others are better suited for eating fruit or sipping nectar. With colors are as varied as their beaks, the honeycreepers and honeyeaters evolved into many different species that eat just about every food the forest has to offer, from seeds to insects to fruit.

The Hawaiian Islands have an extremely high rate of endemic avifauna. In other words, many of Hawai‘i’s native birds are unique to the Hawaiian Islands, and are found nowhere else on Earth. The main reasons that Hawai‘i has so many endemic (unique) bird species are Hawai‘i’s geographic isolation as well as the abundance of ideal bird habitat throughout the Hawaiian Islands.

Original Colonizing Species

Millions of years ago, several families of birds made the long journey to the Hawaiian Islands. Perhaps they were blown off course in a storm, or otherwise lost their way and ended up on the remote archipelago. Those first colonizing bird populations (consisting of probably very few birds) took advantage of the lack of predators in the Hawaiian Islands, and thrived in their new habitats. Eventually the birds multiplied, and over many generations established significant populations throughout the Hawaiian Islands.

Groups of the growing bird populations utilized different food sources and ecological opportunities (niches). Eventually the populations became genetically isolated from one another and evolved into many distinct species.

When one species evolves into many species it is known as adaptive radiation, or evolutionary divergence. In all, about 15 to 20 original colonizing bird populations (from at least 11 different bird families) evolved into well over 100 different bird species in the Hawaiian Islands.

Populations and Extinctions

When the first Polynesians settled in the Hawaiian Islands they immediately began to have an impact on native bird populations. For example, while nēnē (Branta sandvicensis) had once thrived on Kaua‘i, it is believed the bird was extinct on Kaua‘i by the time Captain Cook arrived in 1778, though nēnē populations on other islands, particularly Hawai‘i Island, were still significant.

When Captain Cook arrived in the Hawaiian Islands in 1778, there were about 80 species of endemic Hawaiian landbirds and at least 24 species and subspecies of native Hawaiian seabirds (4 endemic) and at least 34 species and two subspecies of waterbirds (29 endemic). Before Cook arrived, more than 35 endemic Hawaiian landbirds had already gone extinct.

Bird species that went extinct prior to Cook’s arrival met their demise from a variety of causes, including humans hunting the birds for food, feathers, and other reasons (e.g., collectors capturing the birds).

Pigs and dogs brought by the Polynesian settlers of the Hawaiian Islands also had an effect on island bird populations, as did the rats that hitched a ride on the Polynesians’ voyaging canoes. These particular Polynesian-introduced species were detrimental to ground-nesting birds, which were also the most likely birds to be hunted by the early settlers for food.

About 23 of the bird species that became extinct prior to Western contact were ground-nesting birds, now known only from subfossil discoveries. (For a more in-depth discussion of extinct Hawaiian birds, see Overview of Native and Polynesian-Introduced Species of the Hawaiian Islands, Chapter 5.)

Hawaiian Featherwork

Another factor contributing to bird extinctions in the Hawaiian Islands before European contact was the elaborate featherwork that Hawaiian ali‘i (royalty) fashioned from the feathers of various birds, particularly small endemic forest birds such as the ‘ō‘ō (Moho species).

The featherwork produced by the Hawaiians is considered among the finest in all of Polynesia. This is a result of the Hawaiians’ skillful craftsmanship as well as a reflection of the array of colorful bird species found on the Hawaiian Islands.

Hawaiians crafted various items using feathers, including ‘ahu ‘ula, the long royal capes and cloaks worn by ali‘i. Also fashioned from feathers were mahiole, the ceremonial warrior helmets bearing a resemblance to Homeric Greek military helmets.

The coarser seabird feathers (e.g., tail feathers of tropicbirds) were used to make kāhili, the royal feather standards that were symbols of chiefly rank. Feathers were also used to make lei hulu (feather lei), which were worn around the head or neck, or untied around the shoulders.

Tropicbirds (koa‘e), frigatebirds (‘iwa), and various other species provided feathers for Hawaiian featherwork, but the most valued plumage was that of the small endemic forest birds. The scarlet feathers of the ‘i‘iwi (Vestiaria coccinea) and the green feathers of the ‘ō‘ū (Psittirostra psittacea) were often used. Above all other feathers, plumage hunters valued the yellow feathers of the ‘ō‘ō (Moho species) and mamo (Drepanis pacifica), two predominantly black birds with tufts of yellow feathers near their wings and tail.

The mamo, which went extinct in the early 1900s, was a mostly black bird with yellow feathers above and below its tail. One royal yellow cape made for King Kamehameha I was said to have required the feathers of about 80,000 birds (mostly feathers of the mamo).

The prized yellow thigh feathers of the ‘ō‘ō (Moho species) were a major factor in that species extinction, island by island. At one point, ‘ō‘ō feathers were even considered more valuable than the lei niho palaoa (whale tooth pendant) made with the teeth of the palaoa (Physeter macrocephalus, sperm whale) and highly prized by ali‘i (royalty). (See Lei Niho Palaoa in Island Flowers and Lei section, Chapter 3.)

A unique variety of ‘ō‘ō on Kaua‘i was referred to as the ‘ō‘ō ‘ā‘ā (Moho braccatus). Of the four species of ‘ō‘ō in the Hawaiian Islands, the Kaua‘i species likely survived the longest because it lacked the bright yellow wing feathers of the other ‘ō‘ō species and these yellow feathers were desired for use in featherwork.

The last sighting of the ‘ō‘ō‘ā‘ā occurred in Kaua‘i’s Alaka‘i Swamp in 1987. With a variable and echoing song, the bird was known as one of the finest singers of all the Hawaiian birds.

In ancient times, birds captured for Hawaiian featherwork were caught by a variety of methods, including using fine mesh nets made from olonā (Touchardia latifolia).

The birds were also caught by smearing the gummy sap from certain plants onto a stick, and catching the birds when they alighted upon the sticky substance. Used for this purpose was the sap of ‘ulu (Artocarpus altilis, breadfruit), as well as pāpala kēpau (Pisonia species), ‘āla‘a (Pouteria sandwicensis) and other trees.

An ancient Hawaiian proverb states, “E hō‘ike mai ana ka lā‘au a ke kia manu,” (“The stick of the birdcatcher will tell”), meaning “...we will know how successful one is by what he produces. One knew whether a birdcatcher was successful by counting the birds on his gummed stick.”[ii]

Hawaiian Honeycreepers

The Hawaiian Islands are considered by scientists to be one of the world’s most fascinating natural laboratories of genetics and biology. A prominent example: about 50 unique species or subspecies of Hawaiian honeycreeper birds evolved from a single colonizing population of finches.

Many of these bird species are now extinct. As of 1995, only 21 honeycreeper species or subspecies remained, and 14 of those were listed as endangered.

Researchers theorize that the original colonizing finches first took hold on the Hawaiian archipelago sometime between 15 and 30 million years ago. At that time, the eight main Hawaiian Islands had not yet come into existence. Kaua‘i is only about five million years old, and the other main Hawaiian Islands are even younger.

The basaltic rocks of Midway Atoll, 1,580 miles (2,543 km) northwest of the island of Hawai‘i and 1,309 miles (2,107 km) northwest of Honolulu, have been dated to nearly 28 million years old.

The original colonizing finch birds inhabited the islands that were the predecessors to today’s Hawaiian Islands. These ancient islands have now been carried northwest by the Pacific Plate and eroded away.

Once a bird species took hold on the emerging island chain, it then populated each successive island over time. This trans-migration between geologically changing habitat was occurring even as the birds themselves continued to evolve into a multitude of new and different species.

Evolutionary Processes / Adaptive Radiation

Honeycreepers are one of the most studied examples of adaptive radiation in the field of evolutionary biology. After the original colonizing population of finches arrived, they began to increase in numbers and spread throughout the Hawaiian Islands.

They inhabited different areas and utilized different food sources, each sub-population taking advantage of different ecological opportunities (niches).

A great diversity of beak shape, tongue morphology, and feather color evolved in the different bird populations. The birds also developed a wide variety of songs and behaviors.

Natural selection favors physical traits that are beneficial to survival in the particular environment in which the animal lives. When different sub-groups of the original finch population became reproductively isolated from each other, they eventually began to possess very different physical traits from one another.

Some bird species developed powerful, seed-eating bills that were thick, short and efficient for cracking seeds. Other species evolved more delicate, pointed beaks that were well-adapted for catching insects or sipping nectar. Still others evolved crossed beaks good for probing bark, pecking at woody stems and twigs or opening leafbuds.

The honeycreeper family is a remarkable and world-renowned example of the evolutionary process of adaptive radiation whereby one species evolves into many distinct species. In the case of the honeycreepers, an ancestral population of birds became isolated in various Hawaiian habitats, and then over thousands of generations, evolved into about 50 species and subspecies of unique birds.

One of the most unusual Hawaiian honeycreepers to evolve was the little olive and yellow-colored bird called ‘akia pōlā‘au (Hemignathus munroi), which is federally listed as an endangered species. The ‘akia pōlā‘au developed a small, stout bill on the bottom for pecking, but a long curved, hooked bill on top, which it uses to pry open bark as it explores the trunks of trees for larvae.

[Illustration or Photograph: ‘Akia pōlā‘au]

‘Akialoa and ‘I‘iwi

Some bird species evolved beaks ideal for extracting the nectar from flowers. Two birds with specialized bills for sipping nectar are the ‘akialoa (Hemignathus species) and ‘the ‘i‘iwi (Vestiaria coccinea).

The ‘akialoa is a small olive or yellow-green bird with a long, curved bill. Different subspecies of the ‘akialoa once inhabited different Hawaiian Islands, but today the only one that is not extinct is the Kaua‘i ‘akialoa (Hemignathus procerus), which also has the longest, curved beak.

Federally listed as an endangered species, the ‘akialoa uses its long beak to sip honey from the base of leaves of the hala pepe (Pleomele species) and ‘ie‘ie (Freycinetia arborea).

The ‘i‘iwi is a small, vermilion (red) bird with black wings and tail, and orange legs. The ‘i‘iwi has a pronounced salmon-colored bill that is unusually long and curves downward, and is among the most spectacular of all the honeycreeper bills.

Researchers believe that the ‘i‘iwi evolved a long, down-curving bill because it fit perfectly into the deep corolla (the petal array) of certain native lobelias (Lobelioideae) with long, tubular-shaped flowers. (See Introduction to Native Plants and Ferns of the Hawaiian Islands, Chapter 8.)

These lobelia flowers likely evolved their long, curved corolla at the same time that the ‘i‘iwi evolved a long and curved bill to fit into the flower. Both species benefited, with the flower providing food for the bird, and the bird pollinating the flower (the stamen delivers pollen on the bird’s forehead). Eventually only the ‘i‘iwi had the proper beak to gain access to the nectar of this particular long-throated flower, aiding the survival of the flower species as well as the bird.

When two species (in this case a bird and a flower) evolve together to the benefit of each, it is known as co-evolution. The two species are also said to have a symbiotic relationship, with both species benefiting from the other.

[Photograph: ‘Akialoa]

Today many of the native lobelioid flower species are very rare or extinct, and the i’iwi has adapted to this change in food supply by feeding on the blossoms of the ‘ōhi‘a lehua tree (Metrosideros species). The ‘ōhi‘a blossom has no petals or corolla, so from an evolutionary standpoint the ‘i‘iwi’s long beak is no longer necessary for feeding.

Researchers have noted that, as evolutionary theory would predict, the ‘i‘iwi’s beak now seems to be evolving shorter again over time. A comparison of current ‘i‘iwi beaks with museum species from 1902 shows that ‘i‘iwi beaks have indeed become 3% shorter. The bird is apparently undergoing a sort of reverse evolution, in which a trait (a long, decurved beak) that formerly evolved because it was beneficial is now disappearing because it has no particular benefit.

[Illustration or Photograph: ‘I‘iwi feeding on lobelia.]

One of the most commonly seen of the honeycreepers is the ‘apapane (Himatione sanguinea), which survives on all of the main Hawaiian Islands. Its deep crimson color is very similar to the color of the ‘ōhi‘a lehua (Metrosideros species) blossom upon which the bird feeds.

[Photograph: ‘Apapane feeding on ‘ōhi‘a lehua blossom.]

Many Hawaiian species exist in just one location, making them extremely vulnerable to extinction and dependent on the last remote pockets of native habitat. For example, the endangered crested honeycreeper (Palmeria dolei) lives only on the upper eastern slopes of Maui’s Haleakalā Volcano in forests of ‘ōhi‘a lehua (Metrosideros species) above 4,500 feet (1,372 m).

The ‘Elepaio

The ‘elepaio (Chasiempis sandwichensis) is a small bird with a gray back, blackish tail, and white rump, was also able to adapt to the changing environment of the Hawaiian Islands. Not a honeycreeper, the ‘elepaio is a member of the flycatcher family (Muscicapidae). The bird’s name comes from its song, which sounds like e-le-pa-i-o, and is also described as a squeaky "wolf-whistle.”

[Photograph: ‘Elepaio]

‘Elepaio feed on insects and weave small nests of roots and grass. They lay usually two or three eggs, and the hatchlings fledge (learn to fly) in about two weeks. Variety has evolved in the ‘elepaio’s different populations, which look different on each Hawaiian Island.

Canoe makers of ancient Hawai‘i considered the ‘elepaio as their friendly guardian spirit. The bird was said to guide canoe builders to the best koa trees (Acacia koa) for use as hulls for their voyaging canoes.

If an ‘elepaio landed in a tree and spent some time pecking at it, then the tree was considered unsuitable for canoe building. However, if the bird landed on the tree and then began singing that was a good omen, and meant the tree would be a good one to use for building a canoe.

An ancient proverb states, “Ua ‘elepaio ‘ia ka wa‘a.” (“The ‘elepaio has [marked] the canoe [log]”), meaning “...there is an indication of failure. Canoe makers of old watched the movements of the ‘elepaio bird whenever a koa tree was hewed down to be made into a canoe. Should the bird peck at the wood, it was useless to work on that log, for it would not prove seaworthy.”[iii]

One of the most recent additions to the federal endangered species list is the O‘ahu ‘elepaio (Chasiempis sandwichensis ibidis). The bird inhabits less than 5% of its former range, which has declined nearly 90% since 1940. Sightings have dropped precipitously since 1960.

The O‘ahu ‘elepaio is now found in just seven small populations near the Wai‘anae and Ko‘olau Mountains, with an estimated total population of between 200 and 500 birds.

The Puaiohi—Captive Breeding

Many of native Hawaiian bird species are endemic to just one island. For example, in the Alaka‘i Swamp lives the puaiohi (Myadestes palmeri), a little pink-legged bird found nowhere else on Earth. Also called the small Kaua‘i thrush, the puaiohi is found only in the uplands of the Garden Island.

The puaiohi has an olive-brown back and a gray belly, and likes to nest in holes on cliffs. Puaiohi feed on native fruits, such as ‘ōlapa (Cheirodendron species) and pilo (Capparis sandwichiana), as well as insects.

[Photograph or Illustration: Puaiohi]

An extremely endangered species, the puaiohi’s population was at one point believed to be less than 30 birds. Then in 1995 scientists learned more about their habitat and discovered more of these rare birds. The population is now estimated to be about 250.

Some puaiohi are being raised in captivity at the Keauhou Bird Conservation Center on the island of Hawai‘i, a project sponsored by the Peregrine Fund, and the Zoological Society of San Diego with the approval of the state Board of Land and Natural Resources. At least 47 captive-raised birds have been released in the wild and have produced many new nests and fledglings.

The San Diego group also manages the endangered bird facility at Olinda, Maui. The Maui facility is engaged in captive propagation of nēnē (Branta sandvicensis, Hawaiian goose), ‘alalā (Corvus hawaiiensis, Hawaiian crow), and other species.

Researchers plan on using the propagation techniques that were successful with the puaiohi to breed the endangered Maui parrotbill (Pseudonestor xanthophrys) and the Big Island palila (Loxioides bailleui).

Released birds are fitted with transmitters to gain more information that helps in the effort to prevent the extinction of the species. For example, a puaiohi nest observed in 1999 near a streamside cliff on a fallen log was determined to be the nest of two captive-bred puaiohi that had earlier been released in the wild.

Threats to Endemic Forest Birds

Avian malaria and avian pox are two of the primary causes of the endangerment and extinctions of small endemic Hawaiian forest birds. Other major factors affecting forest bird populations include habitat destruction resulting from agriculture, ranching, and urban development, as well as predation by mongoose and domestic animals (cats and dogs).

Cattle, deer, sheep, goats, and pigs have destroyed large amounts of native Hawaiian habitat. Introduced bird species also compete with native bird species for habitat and food sources.

In the past, human hunting has also played a major role in reducing native bird populations, including the extinctions of several flightless bird species that were apparently captured by Hawaiians who utilized the ground-nesting birds for food and feathers before Captain Cook arrived in the Hawaiian Islands in 1778 establishing Western contact.

Archaeological evidence has revealed that ancient Hawaiians also utilized various other bird species for food and/or feathers, including shearwaters and petrels. (See Overview of Native and Polynesian-Introduced Species of the Hawaiian Islands, Chapter 5.)

[i] p. 72, Pukui, Mary Kawena. ‘Ōlelo No‘eau: Hawaiian Proverbs & Poetical Sayings. Honolulu: Bishop Museum Press, 1983. Proverb 639.

[ii] p. 36, Pukui, Mary Kawena. ‘Ōlelo No‘eau: Hawaiian Proverbs & Poetical Sayings. Honolulu: Bishop Museum Press, 1983. Proverb 287.

[iii] p. 306, Pukui, Mary Kawena. ‘Ōlelo No‘eau: Hawaiian Proverbs & Poetical Sayings. Honolulu: Bishop Museum Press, 1983. Proverb 2777.