Part 3: Threats to Native Species

Part 3—Endangered Species and Extinctions

Currently at least 30 species and subspecies of Hawaiian birds are federally listed as endangered, along with one subspecies listed as threatened.[i] About half of the Hawaiian Islands’ endemic birds are already extinct.

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

At least 24 native Hawaiian bird taxa (species and subspecies) have gone extinct since 1778, from the Laysan rail (Porzana palmeri), which was last seen in 1944, to the Greater koa finch (Rhodacanthis palmeri), last seen in 1896. The Hawai‘i ‘ō‘ō (Moho nobilis), a bird long sought after for its beautiful feathers (see Native Birds of the Hawaiian Islands, Chapter 7) for use in ‘ahu ‘ula (royal cloaks), hasn’t been seen since 1934.[ii]

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

Also extinct or likely extinct are 97 taxa (species and subspecies) of plants, 72 taxa of snails, and 74 taxa of insects.[iii] The presumably extinct insects 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).[iv]

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

These species include more than 275 endangered taxa (species and subspecies) of plants and more than 35 endangered vertebrate species, with at least another 40 invertebrate species listed as threatened.

The Manual of the Flowering Plants of Hawai‘i (1999) notes that, of the 1,094 taxa (including species and subspecies) of native Hawaiian plants included in the text, “...423 (38%) are considered to be extinct or threatened to some degree; of these taxa, 107 are presumed extinct (10% of the native taxa), 139 endangered (12%), 39 vulnerable (4%), and 138 rare (12%).”[v]

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 categories listed above.

Though the Hawaiian Islands are just two tenths of one percent of the size of the United States, the Hawaiian Islands account 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 all birds listed as endangered. More than half of the Hawaiian Islands’ endemic plants are now threatened, endangered, or extinct, along with about half of the Hawaiian Islands’ endemic birds.

Threats to Native Species—Before 1778

The first threats to native species of the Hawaiian Islands came from the ancient Polynesian settlers of the Hawaiian Islands, who brought pua‘a (Sus scrofa, pigs), moa (Gallus gallus gallus, chickens), and ‘īlio (Canis familiaris, dogs), as well unintentional species introductions that came as stowaways on the voyaging canoes, including geckos (Gekkonidae), skinks (Scincidae), rats (Rattus exulans), and several other species (see above).

Early Hawaiian settlers also 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. (See Native Birds of the Hawaiian Islands, Chapter 7.)

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.

In the decades after Captain Cook’s first visit to the Hawaiian Islands, the landscape of the 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.

The Chinese market for sandalwood (Santalum species) also 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, particularly populations at lower elevations (where most of the alteration of the landscape took place).

Due to this habitat loss as well as mosquito-borne diseases (e.g., avian malaria), the last surviving species of these small and endangered, endemic Hawaiian birds are now restricted to the higher elevations.

Threats to Native Species—Post-Contact

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 lizards have become established in some areas, including skinks, chameleons, geckos, anoles, and iguanas. (See Geckos and other Reptiles, Chapter 10.)

After Western contact with the Hawaiian Islands was established in 1778, the influx of new species was rapid, and had devastating effects on native species. These introduced species (also known as alien, exotic, adventive, or introduced species) included birds, lizards, plants, and animals that detrimentally affected native species of the Hawaiian Islands.

Some introduced species destroyed native habitats while other preyed on native species or competed with native species for food. Today, 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 the island of Hawai‘i 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 began to be 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 the island of Hawai‘i. Goats and pigs are now found on all of the Hawaiian Islands with the exception of Lāna‘i.

Ka i‘a holehole iwi o ka ‘āina.

The fish of the land that strips the flesh from the bones.

Goats. When one pursues them for meat, many a limb

suffers skinning and bruises.

Pukui: 1337-145

Two species of sheep may be found on the upper elevations of Mauna Kea Volcano on the island of Hawai‘i. 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 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 species and ecosystems of the Hawaiian Islands.

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 as well as the native Hawaiian species they support.

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.

A Summary of the Primary Threats to Native Species of the Hawaiian Islands

Historically, the primary threats to native species have included:

Ø The destruction of native habitat by hoofed animals (e.g., cattle, sheep, pigs, and goats).

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

Ø Predation by non-native domestic (and feral) animals such as cats (Felis domesticus) and dogs (Canis familiaris).

Ø 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 (see above).

Ø Hunting of birds (by humans) for food, feathers, and for other reasons.

Ø Competition from aggressive non-native species, such as the Banana Poka vine (Passiflora mollissima) that blankets large areas of native forest and strangles native trees.

Native Hawaiian plants now compete with more than 1,000 introduced plant species. Native bird species also must compete for habitat with introduced species, such as the barn owl (Tyto alba).

Ø Parasites and foreign diseases spread by non-native species (e.g., mosquitoes spreading avian malaria and avian pox to native forest birds). Many of the Hawaiian Islands’ native species are particularly vulnerable to foreign diseases.

Ø Introduced insects harmful to native species. For example, native kou trees (Cordia subcordata) were devastated by an introduced moth species.

Ø Loss of native habitat to agricultural enterprises, particularly sugarcane (Saccharum officinarum) and pineapple (Ananas comosus).

Ø The demand for fine woods, such as sandalwood (Santalum species) and koa (Acacia koa), leading to the harvesting of native trees.

Ø Loss of habitat due to construction of homes and commercial developments.

Preventing Extinctions

The biological diversity of the Hawaiian Islands is astonishing: lush rainforests, underwater coral reefs, coastal dunes, subterranean lava tubes, and many other ecosystems support a variety of life forms. Unfortunately, many Hawaiian species cling tenuously to survival in remote and diminishing native habitat.

The combined efforts of scientists and concerned local citizens are helping to preserve native ecosystems and prevent extinctions. For example, there has been and continues to be a concerted community effort to rescue stranded wedge-tailed shearwater birds (Puffinus pacificus chlororhynchus). (See Newell’s and Wedge-Tailed Shearwaters section in Native Birds of the Hawaiian Islands, Chapter 7.)

Other community volunteer efforts attempt to eradicate introduced plant species that threaten native ecosystems. One such event is the Banana Poka Festival in Kaua‘i’s Kōke‘e State Park.

Many native Hawaiian species are little known and even less seen. Scientists estimate that there are thousands of native Hawaiian species still unknown to science.



[i] 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.

[ii] Bishop Museum: Hawai‘i’s Extinct Species—Birds. Internet site: http://hbs.bishopmuseum.org/endangered/ext-birds.html, 7/28/2002.

[iii] Bishop Museum - Hawaii’s Extinct Species. Internet site: http://hbs.bishopmuseum.org/endangered/extinct.html, 7/28/2002.

[iv] Bishop Museum - Hawaii’s Extinct Species: Insects. Internet site: http://hbs.bishopmuseum.org/endangered/ext-insects.html, 7/28/2002.

[v] Wagner, Warren L., Herbst, Derral R., and Sohmer, S.H. Manual of the Flowering Plants of Hawai‘i: Revised Edition, Volumes 1 and 2. Honolulu: University of Hawai‘i Press; Bishop Museum Press, 1999.