Native Species of the Hawaiian Islands

Relatively few species were able to reach the Hawaiian archipelago before humans arrived, but those original colonizing species evolved into an incredible array of uniquely adapted species that gradually transformed the barren and rocky volcanoes of the Hawaiian Islands into lush tropical islands full of life.

The extreme isolation of the Hawaiian Islands, more than 2,400 miles (3,862 km) from the nearest continental land mass, led to the evolution of thousands of endemic (unique) species of flowering plants, ferns, insects, birds, and marine life.

Native species of the Hawaiian Islands are divided into two categories: indigenous and endemic. Indigenous species are native to the Hawaiian Islands and also native to some other location. Without the aid of humans, they arrived in the Hawaiian Islands by “wind, wave, or wing”—in other words, they were carried by winds, the ocean, or birds.

Endemic species evolved in the Hawaiian Islands from an indigenous (native) species already established in the Islands. Endemic species are native to the Hawaiian Islands and nowhere else. Thus, all native Hawaiian species either came from somewhere else (indigenous), or evolved from species already established in the Hawaiian Islands (endemic).

The extreme isolation and rich diversity of habitats in the Hawaiian Islands led to an extremely high rate of endemic species. Overall, about half of the native species of the Hawaiian Islands are endemic.

A total of 23,680 Hawaiian species have been documented, including 18,607 native Hawaiian species (9,151 indigenous species and 9,456 endemic species), and 5,073 human-introduced (non-native) species.[i]

The endemic, indigenous, and introduced species of the Hawaiian Islands include plants, trees, mollusks (e.g., snails), invertebrates (e.g., insects), fish, birds, reptiles (e.g., sea turtles), mammals (e.g., bats, monk seals, whales and dolphins), fungi, lichens, protists (including algae and human parasitic protists), and helminths. Viruses and bacteria were not included in the species count.

Bishop Museum scientists have done extensive studies to determine the total number of species found in the Hawaiian Islands, and have assembled a comprehensive tabulation of scientifically documented species, published by Bishop Museum and updated annually, including the Records of the Hawaii Biological Survey for 2000, (Evenhuis, Neal L., and Eldredge, Lucius G., Editors. Bishop Museum Occasional Papers, Number 68, 69. Honolulu: Bishop Museum, 3/25/2002.)

The Hawaii Biological Survey is a Bishop Museum program that was established in 1992 by Hawai‘i’s State Legislature to maintain an ongoing inventory of the natural history of the Hawaiian Islands, including non-native as well as native species

The documented native Hawaiian species include: 1,163 flowering plants (918 endemic); 719 other native plants (241 endemic), 178 ferns (124 endemic), and 22 fern allies (7 endemic); 1,243 mollusks (962 endemic); 1,143 fish species (149 endemic); 4 reptiles (sea turtles, none endemic); 241 bird species (63 endemic); and 25 mammals (2 endemic).

These mammals include the endemic ‘ilio-holo-i-ka-uaua (Hawaiian monk seal) and ‘ōpe‘ape‘a (Hawaiian hoary bat), as well as 23 indigenous marine mammal species. 1,995 protist species (82 endemic); 2,088 fungi and lichen species (240 endemic);[ii] and 9,270 native invertebrates (7,239 endemic).

These native Hawaiian invertebrates include 6,284 arthropods, along with 1,743 other invertebrates (449 endemic). The arthropods include 5,818 insect species (5,462 endemic) and 466 other arthropods (366 endemic).

Native Plants

Before Western contact began to drastically change the landscape of the Hawaiian Islands, there were more than 1,700 known native Hawaiian plant species, including more than 1,000 native flowering plant species that had evolved from less than 300 original immigrants. At least 178 native ferns evolved from about 135 colonizing species.

The 1999 Manual of the Flowering Plants of Hawai‘i: Revised Edition (Wagner, Warren L., Herbst, Derral R., and Sohmer, S.H. Honolulu: University of Hawai‘i Press; Bishop Museum Press, 1999) formally recognized 956 species of native Hawaiian flowering plants, including 850 species that are endemic to the Hawaiian Islands.

Many more native Hawaiian plant species have since been discovered, and are documented in the 2002 Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i (Wagner, Warren L., and Herbst, Derral R. Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002) as well as the Records of the Hawaii Biological Survey (Evenhuis, Neal L., and Eldredge, Lucius G., Editors. Bishop Museum Occasional Papers, Number 68, 69. Honolulu: Bishop Museum, 3/25/2002) with a current total of at least 1,882 documented native Hawaiian plant species (1,159 endemic), including 1,163 native flowering plant species (918 endemic).

The extremely high rate of flowering plant endemism (79% endemic) in the Hawaiian Islands is primarily attributed to the geographical isolation of the Hawaiian Islands in the middle of the Pacific Ocean, thousands of miles from any continent. The Polynesian settlers of the Hawaiian Islands also brought at least 24 species of plants to Hawai’i, and may have brought as many as 30 plant species or more. (See Polynesian-Introduced Plants.)

About 79% of native flowering plant species in the Hawaiian Islands are endemic along with about 70% of native ferns and 26% of native birds, though nearly all native Hawaiian land bird species are endemic. About 94% of native Hawaiian insect species are endemic, as are 77% of native mollusks, 78% of native invertebrates, and 13% of native fish, including 25% of native reef fish species.

Fish

Of the 24,000 known species of fish in the world, about 1,143 are native to the Hawaiian Islands, including 149 endemic fish species.

About 536 of these fish species are inshore fishes found near reefs and other nearshore areas to a depth of about 200 feet (61 m). About 25% of these 536 inshore species are endemic to the Hawaiian Islands.

The overall rate of endemism for native Hawaiian fish is about 13% (149 endemic species and 994 indigenous species).

Native Hawaiian fish also include five freshwater species, known as ‘o‘opu, which spend part of their lives in the ocean. The endemic āholehole fish (Kuhlia sandvicensis, young stage of āhole, Hawaiian flagtail) sometimes enters lower stream areas, as do pua ‘ama‘ama (Mugil cephalus, young stage of ‘ama‘ama, mullet).

‘Ama‘ama were the main fish raised in ancient Hawaiian loko i‘a (fishponds). Also raised in fishponds were awa (Chanos chanos, milkfish), which reach a length of 6 feet (1.8 m).

At least 41 known species of sharks may be seen in Hawaiian waters (and are thus considered native to the Hawaiian Islands), and 20 of these shark species inhabit deep waters. This includes the viper shark (Trigonognathus kabeyai) reported in: Evenhuis, Neal L., and Eldredge, Lucius G., Editors. Records of the Hawaii Biological Survey for 2000. (Bishop Museum Occasional Papers, Number 68, 69. Honolulu: Bishop Museum, 3/25/2002.)

Six shark species are relatively common around the Hawaiian Islands. Five ray species are native to the Hawaiian Islands, including a manta ray, an eagle ray, and three stingray species.

There are at least 38 native Hawaiian species of moray eel (Muraenidae), along with 16 native species of snake eels (Ophichthidae) and three native species of conger and garden eels (Congridae).

Reptiles and Amphibians

No terrestrial reptiles or amphibians are considered native to the Hawaiian Islands, though there remains a possibility that some lizard species arrived in the Hawaiian Islands on their own. Marine reptiles native to the Hawaiian Islands include five sea turtle species, some seen only rarely in Hawaiian waters.

The two sea turtle species that come onto Hawaiian shores to lay their eggs are honu (Chelonia mydas, green sea turtle) and honu‘ea (Eretmochelys imbricata, hawksbill sea turtle).

Another marine reptile occasionally seen in Hawaiian waters (and thus considered native) is the yellow-bellied sea snake (Pelamis platurus), a venomous yellow and black reptile that is about 29 inches long. A distant relative of the cobra, the yellow-bellied sea snake is the only truly pelagic (open-ocean) sea snake of 55 known sea snake species.

Three skink species and four gecko species were established in the Hawaiian Islands before Western contact. These species likely came as stowaways aboard the voyaging canoes of the Polynesian settlers of the Hawaiian Islands, though it is possible some of these lizards may have reached the Hawaiian Islands on their own (e.g., by rafting on a log or on other ocean debris).

As of 2004 at least 21 lizard species have been found in the wild in the Hawaiian Islands (and thus are assumed to have established breeding populations). These lizards include geckos, skinks, anolis lizards, chameleons, horned lizards, and iguanas.

Some of these lizard species are found throughout the Hawaiian Islands, while others are only found in very small areas on particular islands. Three of the lizard species are (presumably) no longer found in the wild in the Hawaiian Islands.

No terrestrial snakes are native to the Hawaiian Islands, but there is one introduced snake species, called the Island blind snake (Ramphotyphlops braminus), which arrived in the Hawaiian Islands sometime around the 1930s in the soil in potted palm trees imported from the Philippines for landscaping.

Now well established in the Hawaiian Islands, the Island blind snake is a burrowing snake that is about 6½ inches (17 cm) long, feeds on insects and small invertebrates, and spends most of its life underground.

Mammals

There are 78 species of cetaceans worldwide, including all whales, dolphins, and porpoises. At least 22 cetacean species are considered native to the waters surrounding the Hawaiian Islands, though some are only occasionally seen near the Hawaiian Islands.

The 22 native Hawaiian cetacean species include: the humpback whale (Megaptera novaeangliae); fin whale (Balaenoptera physalus); Bryde’s Whale (Balaenoptera edeni); sperm whale (Physeter macrocephalus); right whale (Eubalaena glacialis); pilot whale (Globicephala macrorhynchus); orca, or killer whale (Ornicus orca); false killer whale (Pseudorca crassiden); pygmy killer whale (Feresa attenuata); melon-headed whale (Peponocephala electra); pygmy sperm whale (Kogia breviceps); dwarf sperm whale (Kogia simus); minke whale (Balaenoptera acutorostrata); bottlenose whale (Hyperoodon ampullatus); Cuvier’s beaked whale (Ziphius cavirostris); and the Blainville’s beaked whale (Mesoplodon densirostris).

Aside from these cetacean species, the only native Hawaiian sea mammal is the ‘ilio-holo-i-ka-uaua (Monachus schauinslandi, Hawaiian monk seal, which often feeds near shore and then rests during the day on beaches around the Hawaiian Islands.

The only native Hawaiian land mammal is the ‘ōpe‘ape‘a (Lasiurus cinereus semotus, Hawaiian hoary bat), a furry insect-eating bat that weighs in at about 6 ounces (170 gm) with a wingspan up to 14 inches. (36 cm)

Gastropods

The Bishop Museum’s Hawai‘i Biological Survey has documented at least 781 terrestrial gastropods (759 endemic), and 7 Hawaiian freshwater gastropods (all endemic).

Endemic Hawaiian tree snails (terrestrial gastropods) provide another astounding example of adaptive radiation in the Hawaiian Islands, with more than 750 endemic species having evolved from just a few pioneers that reached the Islands several million years ago, probably in the feathers of migratory birds, or in mud on the birds’ feet.

The snails are known by the Hawaiian name pūpū kani oe (“shell that sounds long”), referring to the belief that the snails sing.

Endemic Hawaiian land and freshwater snails evolved from about 25 colonizing species. These extremely adaptable snails had no natural predators, and were once found in a wide variety of habitats where they fed on the fungi that grow on leaves and forest debris (making the snails an important component of native ecosystems).

The snails were known to vary considerably from valley to valley, and exhibited many shapes and colors, from gold tints to cream-colored with brown stripes.

Unfortunately, these native terrestrial snails have a very slow reproductive cycle as well as a low birthrate, and populations were significantly diminished by collectors and other causes.

The snails are extremely vulnerable to non-native predators, particularly rats (Rattus exulans; R.. rattus; R. norvegicus); introduced snails (e.g., Euglandina rosea, the “cannibal snail,”); and the New Guinea flatworm (Platydemis manokwari), which was introduced to the Hawaiian Islands in the 1990s and now threatens the last, high-elevation habitats of the native snails. (Hadfield, Michael G. Hawaiian Tree Snails, in the Atlas of Hawai‘i: Third Edition. Edited by Sonia P. Juvik and James O. Juvik. Honolulu: University of Hawai‘i Press, 1998.)

There were once more than 300 native Hawaiian snail species in the family Amastridae, but only about 12 or fewer of these species survive today. Recent research studying genetic mutation rates has shown that dozens of tree snail species in the subfamily achatinellinae originated from a single ancestor that likely lived in O‘ahu’s Ko‘olau mountain range about three million years ago.

The last remaining habitat of native Hawaiian terrestrial snails is at high elevations on Moloka‘i, Lāna‘i, and O‘ahu, as well as some middle elevation areas on the islands of Hawai‘i and Maui.

Three brackish/freshwater snail species are endemic to the Hawaiian Islands. Two of these species, hapawai (Neritina vespertina) and pīpīwai (Theodoxus cariosus), prefer brackish waters, while a third species, hīhīwai (Neritina granosa) lives in freshwater stream areas.

There are four native species of lymnaeid snails (pond snails) that live in streams and ponds as well as lo‘i kalo (taro patches). (Yamamoto, Mike N., and Tagawa, Annette W. Hawai‘i’s Native & Exotic Freshwater Animals. Honolulu: Mutual Publishing, 2000.)

Overall, at least 1,243 native Hawaiian mollusks have been documented, and about 80% of these mollusk species are snails, sea slugs, and related species. Native Hawaiian mollusks are invertebrates that evolved from about 25 original immigrant species.

There are also thousands of other native Hawaiian species of invertebrates (animals without backbones), including crabs, shrimp, and sea urchins.

Two native Hawaiian shrimp species, ‘ōpaekala‘ole (Atyoida bisulcata) and ‘ōpae ‘oeha‘a (Macrobrachium grandimanus), live in streams, while a third, ‘ōpae ‘ula (Halocaridina rubra) prefers anchialine ponds that are connected to the sea only by the percolations of saltwater and freshwater through lava rock. Heteromyenia baileyi is a native (indigenous) freshwater sponge that sometimes attains a bright green color.

Algae and Coral

More than 860 marine and freshwater algae species are native to the Hawaiian Islands, including at least 80 endemic algae species. Of the more than 340 known native Hawaiian species of red limu, at least 67 are endemic and most are edible.

There are at least 150 different native Hawaiian coral species (approximately 20 to 30 percent are endemic), including 47 hard stony corals and more than 100 species of sea fan and other soft corals.

Arthropods

Arthropods are invertebrates (animals without backbones), and have a rigid external skeleton as well as segmented body parts and segmented legs (arthropod means “jointed feet”).

At least 6,284 native Hawaiian arthropods have been documented. About 95% of Hawaiian arthropods are insects, while the other 5% are closely related species that are not true insects, including centipedes, millipedes, spiders, and many others.

More than 94% of the 5,818 known native Hawaiian insect species are endemic to the Hawaiian Islands. These 5,462 endemic insect species evolved over a period of at least 30 million years, inhabiting the ancient islands of the Hawaiian archipelago.

At least 23 species and subspecies of damselflies are endemic to the Hawaiian Islands along with five endemic dragonfly species. Many more introduced damselfly and dragonfly species are now established in the Hawaiian Islands.

Two butterfly species are native to the Hawaiian Islands, along with about 13 more introduced butterfly species. More than 60 cave species (living in caves), are native to the Hawaiian Islands, and many of these are endemic to particular islands.

Pomace flies, (Drosophilidae and Scaptomyza), are a renowned example of adaptive radiation among insect fauna of the Hawaiian Islands, with at least 860 documented species of Drosophilidae (in five genera), and perhaps many more yet to be described.

All of these flies apparently evolved from a common pair of ancestors that lived in the Hawaiian Islands about 10 million years ago.

For thousands of generations (over millions of years) the flies reproduced, and island-hopped from one volcano to the next as the islands eroded away at the northwest end of the chain and emerged at the southeast end of the chain.

Currently there are at least 2,161 known beetle species native to the Hawaiian Islands, and at least 1,416 of these beetle species are endemic to the Hawaiian Islands.

There are more species of beetles than any other organism in the Hawaiian Islands, and the Hawaiian Islands also have the world’s highest proportion of beetles to other living things.

Thousands of species of native Hawaiian insects have yet to be scientifically described. It is estimated that the total number of native Hawaiian insects could exceed 10,000 species, evolved from less than 500 original colonizing species. (Howarth, F.G., and Mull, W.P. Hawaiian Insects and their Kin. Honolulu: University of Hawai‘i Press, 1992.)

Also now established in the Hawaiian Islands are more than 550 introduced terrestrial arthropods and more than 2,700 non-native (introduced) insect species.

Hawaii Biological Survey

F.R. Warshauer, in The Atlas of Hawai‘i: Third Edition (1998), and relying in part on the Bishop Museum’s Hawaii Biological Survey, reported 142 native bird species (including extinct species); 7,800 described arthropods (out of an estimated 10,000 to 12,000 native Hawaiian arthropods); 1,300 vascular plants; 1,600 lower plants; 788 mollusks, 166 other invertebrates; and one mammal (not counting marine mammals), totaling about 15,000 native species in those categories. (Warshauer, F.R. Alien Species and Threats to Native Ecology, in the Atlas of Hawai‘i: Third Edition. Edited by Sonia P. Juvik and James O. Juvik. Honolulu: University of Hawai‘i Press, 1998.)

Counts of indigenous and endemic Hawaiian species are constantly changing as researchers discover new species, analyze relationships between species (and subspecies) and further refine scientific classifications.

Initial Colonizing Species—Adaptive Radiation

Indigenous species inhabiting the Hawaiian Islands arrived by a variety of methods. Birds came to the Hawaiian Islands on their natural migration tracks or arrived after being blown off course by a storm.

Seeds floated to the Hawaiian Islands on the ocean, were carried in the wing feathers and digestive tracts of birds, or in mud on the birds’ feet. Also likely embedded in the mud were tiny snails, insects, and other species.

Logs or rafts of debris floating on the Pacific Ocean washed up on the shores of the Hawaiian Islands perhaps carrying species such as geckos and skinks. Winds lifted tiny insects and spiders high into the jetstream, more than eight miles up, where they were carried out over the Pacific Ocean at more than 120 miles per hour and then set down on the Hawaiian Islands, there to remain and multiply.

Overall, about 39% of native Hawaiian plant species arrived in the stomachs of birds; about 13% arrived in mud on birds’ feet; about 23% arrived after being stuck to the feathers of birds; about 9% arrived on rafts of seaweed or debris on the ocean; and about 1.4% came by floating through the air to the Hawaiian Islands.[iii] There are no native Hawaiian amphibians, terrestrial reptiles, ants, or gymnosperms (e.g., pine trees).

Species assumed to be Polynesian-introduced, but possibly arriving on their own, include the Indo-Pacific gecko (Hemidactylus garnotii); mourning gecko (Lepidodactylus lugubris); stump-toed gecko (Gehyra mutilata); tree gecko (Hemiphyllodactylus typus); azure-tailed skink (Emoia impar); moth skink (Lipinia noctua noctua); and snake-eyed skink (Cryptoblepharus poecilopleurus). Many non-native gymnosperms, amphibians, reptiles and ants are now well-established in the Hawaiian Islands.

The evolutionary process whereby one species evolves into many new species is known as adaptive radiation. The Hawaiian Islands are renowned for their historical record of adaptive radiation, particularly regarding bird and insect species.

Populations of original colonizing species often became divided, with each separated sub-population adapting to different habitats and food sources, and eventually evolving into completely new species.

Adaptive radiation, or evolutionary divergence, allowed the relatively few colonizers of the Hawaiian Islands to develop into the amazingly diverse native flora and fauna in the Hawaiian Islands. For example, just one finch bird species that established itself in the Hawaiian Islands millions of years ago evolved into at least 50 species and subspecies of Hawaiian honeycreepers.

Less than 300 original colonizing flowering plant species evolved into more than 1,100 documented native Hawaiian flowering plant species. Just 29 of these original colonizing plant species evolved into more than half of today’s native Hawaiian flowering plant species.

The geographic isolation and diversity of habitats and food sources in the Hawaiian Islands led to the evolution of many new (endemic) species from the relatively few colonizing species that were able to make it to the Hawaiian Islands and reproduce. This resulted in extremely high rates of endemism for various categories of species (e.g., 94% of native Hawaiian insects are endemic).

The extremely high speciation rate in the Hawaiian Islands is typical of extremely isolated locations. Over hundreds of generations, many plant, animal, and insect species evolved adaptations to the unique conditions found in particular ecosystems, from the shorelines to the peaks of each of the Hawaiian Islands.

Specific adaptations distinguished separate populations that eventually evolved into new species or subspecies endemic (unique) to each particular island. For example, the fragrant mokihana plant and the tiny pink-legged puaiohi bird are found only in the uplands of Kaua‘i.

Some native Hawaiian species are endemic to very small areas, such as the endangered koki‘o ke‘oke‘o (white hibiscus) found only in a few northwest Kaua‘i valleys. Koki‘o ke‘oke‘o (white hibiscus) if sound in the valleys of Limahuli and Hanakāpī‘ai.

Birds Species in the Hawaiian Islands

A total of 495 bird species have been documented in the Hawaiian Islands,[iv] including: 60 endemic resident species;[v] 168 breeding and non-breeding migratory species (some seen only rarely); at least 51 extinct species. At least 35 native Hawaiian birds species became extinct before Cook arrived in 1778, including 32 described from subfossils, and another 16 species that became extinct since 1778.

More than 150 non-native birds that have been seen in the Hawaiian Islands but have not established breeding populations; and at least 46 established non-native species.

This total number of birds documented had been 475 before the addition of 20 new species in the Records of the Hawaii Biological Survey for 2000 (Evenhuis, Neal L., and Eldredge, Lucius G., Editors. Bishop Museum Occasional Papers, Number 68, 69. Honolulu: Bishop Museum, 3/25/2002.), which documented 10 new indigenous species (3 endemic and 7 introduced species), increasing the total number of bird species now established in the Hawaiian Islands to 294 species, including 241 native species (178 indigenous, 63 endemic) and 53 introduced species.

At least 22 species of marine birds are native to the Hawaiian Islands, with a total population of more than twelve million birds. More than 60% of the total population of native Hawaiian marine birds are noddies and terns.

At least 33 species of geese and ducks (many migratory) are native to the Hawaiian Islands, along with five species of waterbirds (all endangered).

The five waterbirds are: Hawaiian black-necked stilt (ae‘o); Hawaiian coot (‘alae ke‘oke‘o); koloa (koloa maoli, Hawaiian duck); Hawaiian moorhen (‘alae ‘ula); and black-crowned night-heron (‘auku‘u).

When Captain Cook arrived in the Hawaiian Islands in 1778, there were about 80 species of endemic (unique) Hawaiian landbirds, along with at least 24 species and subspecies of native Hawaiian seabirds (4 endemic) and 34 species and two subspecies of waterbirds (29 endemic).

Worldwide there are about 9,700 bird species, but only about 2% of these bird species are native to the Hawaiian Islands. More than 35 endemic Hawaiian landbirds had already gone extinct by the time of Cook’s arrival.

Species that went extinct prior to Cook’s arrival met their demise from a variety of causes, including hunting of the birds for food and for feathers. Sometimes the birds were released unharmed after some of the feathers were collected.

Pua‘a (pigs) and ‘īlio (dogs) brought by the Polynesians also had an effect on island bird populations, as did the ‘iole (Polynesian black rats) that hitched a ride on the voyaging canoes.

Polynesian-introduced pigs, dogs, and rats were particularly detrimental to native Hawaiian ground-nesting birds, including flightless ducks, geese, ibises, and rails, which were also the most likely birds to be hunted by humans 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, these species included flightless ducks (four species); flightless ibises (three species); flightless rails (at least 10 species); and flightless geese (six species). Some of the flightless geese species were more than 3 feet (1 m) tall.

Other species that went extinct prior to Western contact included at least four long-legged owl species, one shearwater, one bald eagle, two crow species, one petrel, and a harrier along with more than 21 honeycreeper species and one honeyeater species.

It is possible that some of these bird species may have become extinct prior to Polynesian settlement in the Hawaiian Islands, but most (if not all) of these bird species probably became extinct after the Polynesians arrived in the Hawaiian Islands, but before Cook arrived in 1778 establishing Western contact.

Aia a pohā ka leo o ka ‘a‘o, kāpule ke momona o

ka ‘uwa‘u i ka puapua.

When the ‘a‘o birds’ voices are distinctly heard, the ‘uwa‘u

birds are fat even to the very tails.

The ‘a‘o bird was not heard during the nesting season. When the fledglings emerged and their cries were heard, the season had come when young ‘uwa‘u were best for eating, and the people went to snare them.

Pukui: 32-6[vi]

Since 1778, at least 24 more native Hawaiian land bird species or subspecies have become extinct,[vii] including the native kioea (Chaetoptila angustipluma), last seen in 1859, the Greater koa finch (Rhodacanthis palmeri), last seen in 1896, and the Laysan rail (Porzana palmeri), last seen in 1944. The Hawai‘i ‘ō‘ō (Moho nobilis), a bird long sought after for its beautiful feathers used in Hawaiian featherwork, hasn’t been seen since 1934.[viii]

At least 59 endemic Hawaiian bird species and subspecies are now extinct, and another 30 are currently considered rare or endangered (six may already be extinct). At least 30 species and subspecies of Hawaiian birds are federally listed as endangered, along with one subspecies listed as threatened.[ix]

[Photograph: Hawai‘i ‘ō‘ō (Moho nobilis)]

Plant and Animal Extinctions

Just as the Hawaiian Islands are known as the world capital of endemic species, it may also be considered the capital of extinct species. About 10% of native Hawaiian flowering plants (more than 100 species) have gone extinct in the last century, along with more than 40 Hawaiian insect species.

Also extinct are 72 taxa (species and subspecies) of snails and 74 taxa of insects.[x] Insects presumed extinct include: 15 species of Coleoptera (beetles); five species of Diptera (flies, gnats, and mosquitoes); 15 species of Homoptera (leafhoppers, planthoppers, mealybugs, and scales); 38 species of Lepidoptera (moths and butterflies); one species of Odonata (damselflies and dragonflies); two species of Orthoptera (crickets and grasshoppers); and one species of Hemiptera (true bugs).[xi]

More than one third of the plants and animals federally listed as endangered are Hawaiian. In all, more than 360 Hawaiian species and subspecies are listed as either threatened or endangered under the federal and state Endangered Species Acts.

The federally listed Endangered Species include more than 275 species and subspecies of plants and more than 35 vertebrate species, with at least another 40 invertebrate species listed as threatened.

About 38% of Hawaiian plants are considered extinct or threatened, 10% presumed extinct, 12% endangered, 4% vulnerable, and 12% rare.

Note: The U.S. Fish & Wildlife Service endangered species program (in regards to Hawaiian species) does not count subspecies separately, resulting in different totals and percents in the stated categories.

The Hawaiian Islands are just two tenths of one percent of the size of the United States, but accounts for nearly 70% of the United States’ historically documented plant and animal extinctions. More than 30% of federally listed endangered species are Hawaiian, along with more than 40% of the listed birds.

More than half of endemic Hawaiian plants are now threatened, endangered, or extinct, and about half of the original endemic Hawaiian bird species are already extinct.

This is documented in the Federal Register, 2002, Vol. 67, U.S. Fish & Wildlife Service. Federal Register, 2002, Vol. 67, U.S. Fish & Wildlife Service, Threatened and Endangered Species System (TESS), Listings by State and Territory as of 7/20/2002. Internet site: http://ecos.fws.gov/servlet/TESSWebpageUsaLists?state=HI, 7/28/2002. Twenty-seven species that were presumed to be extinct in the 1990 Manual of the Flowering Plants of Hawai‘i were subsequently rediscovered, and documented as such in the 1999 Manual of the Flowering Plants of Hawai‘i: Revised Edition. (Wagner, Warren L., Herbst, Derral R., and Sohmer, S.H. Honolulu: University of Hawai‘i Press; Bishop Museum Press, 1999.)

In the 2002 Electronic Supplement to the Manual of the Flowering Plants of Hawai‘i (Wagner, Warren L., and Herbst, Derral R.) Internet site: http://rathbun.si.edu/botany/pacificislandbiodiversity/hawaiianflora/supplement.htm, 3/05/2002. at least 32 new species and two new subspecies discoveries are documented, along with one new endemic genus.

The Electronic Supplement also lists numerous name (nomenclatural) changes, “resurrections from synonymy,” and corrections of past misidentifications. Many of these changes have further increased the total number of documented native Hawaiian species and subspecies.

In addition, many more species that were presumed extinct were rediscovered (in addition to the 27 rediscoveries between 1990 and 1999.

Threats to Native Species of the Hawaiian Islands

Ø The destruction of native habitat by non-native hoofed animals (e.g., cattle, sheep, pigs, and goats). In the decades after Captain Cook’s first visit to the Hawaiian Islands, the landscape of the Hawaiian Islands began to be drastically altered by increasing numbers of cattle, sheep, goats, and pigs. The pigs brought by Westerners were significantly larger than those brought to the Hawaiian Islands by the first Polynesian settlers.

Ø Predation on native species by non-native (introduced) rats, including the Polynesian black rat (Rattus exulans) that first came to the Hawaiian Islands as stowaways on the Hawaiian voyaging canoes, and then two other rat species (Rattus rattus and Rattus norvegicus) brought by early European ships.

Ø Predation by the small Indian mongoose (Herpestes auropunctatus), which feeds on the eggs of ground-nesting native birds. Mongoose are now found on all of the main Hawaiian Islands except Kaua‘i.

Ø Predation by non-native domestic and feral animals such as cats (Felis domesticus) and dogs (Canis familiaris). Destruction of native habitat by other non-native species with established breeding populations in the Hawaiian Islands, including axis deer, black-tailed deer, donkeys, wallabies, and Mouflon sheep.

Since Captain Cook established Western contact with the Hawaiian Islands in 1778, thousands of species have been introduced to the Hawaiian Islands accidentally or intentionally, and for various purposes, including pest control and ornamental landscaping. Many escaped pets, such as cats (Felis domesticus), have also established significant wild populations in some Hawaiian forests.

Various non-native lizards have become established in some areas, including skinks, chameleons, geckos, anoles, and iguanas. Sheep, goats, pigs, deer (axis and black-tailed), donkeys, and wallabies run wild in certain areas of the Hawaiian Islands.

The wild donkeys are found on Hawai‘i Island in the region north of the Kona airport near the Kona Village Resort and Four Seasons Hotel. The wild donkeys, known as the Kona Nightingales, are the remnants of a herd that was used to carry coffee from the uplands to the ocean until the end of World War II, when military jeeps were used to carry the coffee and many of the donkeys were released on Hualālai Volcano.

Axis deer are found on Moloka‘i, Maui, and Lāna‘i. Black-tailed deer are found in northwestern Kaua‘i, and feral donkeys are found on Hawai‘i Island. Goats and pigs are now found on all of the Hawaiian Islands with the exception of Lāna‘i.

Two species of sheep may be found on the upper elevations of Mauna Kea Volcano on Hawai‘i Island. One of these species, the Mouflon sheep, is also found on Lāna‘i. Recently, both sheep species have been nearly eliminated in an effort to protect native species.

Thousands of axis deer roam wild on the island of Maui, mostly from Hāna to Kapalua. These deer are the descendants of five deer that were introduced to Maui by State of Hawai‘i officials in 1959, and four more deer brought to Maui in 1960. The deer were initially brought to the Islands to create new hunting opportunities.

Maui’s axis deer population has increased rapidly over the last several decades (approximately doubling about every four years), with significant negative effects on native Hawaiian species and ecosystems. In 2002, the State of Hawai‘i signed a ten-year agreement to continue the availability of Mouflon sheep and axis deer hunting programs on Lāna‘i, where hunters take about 600 sheep and 700 deer each year.

All of the above mentioned non-native feral ungulate species have had significant negative effects on native Hawaiian ecosystems and the native Hawaiian species they support.

Ø An estimated 40 to 250 rock wallabies live in O‘ahu’s Kalihi Valley. Three of the miniature, kangaroo-like marsupials were brought to the Hawaiian Islands from Australia in 1916 to add to the collection of a private zoo. Two of the wallabies escaped, and today’s wild population in Kalihi Valley are their descendants.

Ø Hunting of birds (by humans) for food, feathers, and for other reasons. Early Hawaiian settlers hunted birds for food (e.g., flightless geese, shearwaters and petrels) as well as for feathers (e.g., ‘ō‘ō (Moho species); mamo (Drepanis pacifica); and numerous other species).

The bird feathers were prized for use in ‘ahu ‘ula (royal capes and cloaks), mahiole (feather-crested helmets), kāhili (royal feather standards) and other items of Hawaiian featherwork.

After 1778, hunting by foreigners brought new pressures on many native birds, such as various species of albatross whose eggs and feathers were extensively collected, and the ‘alalā (Corvus hawaiiensis, Hawaiian crows), which were systematically shot by farmers protecting their poultry yards and feed pens.

Ø Predation on young, native waterbirds by various introduced species, including cattle egrets (Bubulcus ibis) and bullfrogs (Rana catesbeiana).

Ø Competition from aggressive non-native plant and animal species, such as the Banana Poka vine (Passiflora mollissima) that blankets large areas of native forest and strangles native trees. Native Hawaiian plants compete with more than 1,000 introduced plant species.

Ø Competition from non-native bird species, such as the barn owl (Tyto alba), that compete with native bird species for habitat.

Ø Parasites and foreign diseases spread by non-native species, such as mosquitoes that spread avian malaria and avian pox, which continue to devastate native forest bird populations, and an introduced moth that devastated native kou trees (Cordia subcordata). Kou (Cordia subcordata) was long thought to be a Polynesian introduction (and not native to the Hawaiian Islands), but was recently determined to be native.[xii]

Ø The high demand for fine native woods, such as sandalwood (Santalum species) and koa (Acacia koa), leading to the illegal harvesting of native trees. The Chinese market for sandalwood (Santalum species) led to deforestation, particularly from 1810 to 1840, the peak years of the sandalwood trade.

Increasing demands for wood and pasture eventually cleared huge areas of the Hawaiian landscape. The loss of native forest habitat decimated many of the endemic Hawaiian bird species.[xiii]

Ø Loss of native habitat to new homes, commercial developments, and agricultural enterprises including sugarcane, rice, pineapple, and coffee.