Hawaiian Honeycreeper Conservation 2
Probably sometime in the 1800’s, a mosquito-transmitted avian disease (avian pox virus) was introduced to the islands, and then in the early part of the 20th century avian malaria reached Hawaii. It is likely that avian malaria spread quickly into these native Hawaiian Honeycreepers (with no prior exposure or natural immunity to this disease) and hastened the decline or extinction of several species. Only in higher elevations where colder temperatures limit the spread of mosquitoes, do native forest bird communities remain relatively intact.
Scientists are attempting to unravel the complexities and impacts of the pox virus and avian malaria in native forest birds with the hope of developing long-term strategies for preventing further extinctions. Meanwhile, the ‘Amakihi, a native honeycreeper, is mysteriously re-populating the lowlands of Hawaii, providing hope for the future of other native birds in Hawaii.
In these two videos you will follow scientists as they learn how the endemic ‘Amakihi is bucking the extinction trend through evolution.
Part One – Hawaiian Honeycreeper Conservation 1
Hawaiian Honeycreeper Conservation 1
The evolution of Hawaiian honeycreepers is an outstanding example of how the Hawaiian islands became home to many species of unique life. About three million years ago, it is suspected a storm from North America led a small flock of finches to Hawaii. These new colonists touched down in a land with many different environments, many different types of food, and few competitors. They spread out over the islands and began evolving in different ways. Some developed long, curved bills to extract nectar from flowers, and others evolved short, stout bills for crushing hard seeds.
When Polynesians voyagers arrived millions of years later they found over fifty unique species and subspecies of honeycreepers – all descended from that one original group. Then in 1826, the first mosquitoes arrived in Hawaii aboard a whaling ship beginning the spread of avian malaria to native birds…
In these two videos you will follow scientists as they learn how the endemic ‘Amakihi is bucking the extinction trend through evolution.
Part Two – Hawaiian Honeycreeper Conservation 2
Hawaiian Birds – Amakihi
The ‘Amakihi is a small, endemic olive green Hawaiian honeycreeper with a short, decurved bill, and is found in native forests on the islands of Hawai‘i, Maui, Kaua‘i, and O‘ahu. The Hawai‘i, Kaua‘i, and O‘ahu ‘amakihi were all considered subspecies under the superspecies Common ‘Amakihi (Hemignathus virens), but recent genetic studies have led to the recognition of the Kaua‘i and O‘ahu ‘amakihi as distinct species. Although considerably diminished in numbers and range, they are still one of the most common birds in native forests.
The ‘Amakihi is found mostly in forests dominated by ohi’a and koa on all islands, and thrive in higher elevations up to the uppermost forest regions of 9,000 feet. The Kauai ‘Amakihi (Hemignatus kauaiensis) is found in the Alakai Wilderness Preserve, Koke’e State Park, and the Makaleha Mountains. The male is generally brighter in color than the female with olive green above, yellowish or creamy gray below, and dark lores. They are nonmigratory and omnivorous, feeding on insects and other arthropods, berries, fruit, nectar, and sap from trees with fully tubular tongues adapted for taking nectar. They are extremely agile and acrobatic while flying and hopping between perches, and can stop suddenly in full flight without slacking speed.
Hawaiian Birds – Akekee Conservation
The ‘Akeke’e population was once relatively stable, even while other endemic Kaua’i birds were sharply declining, and its population was estimated to be nearly 8,000 birds in 2000. However, the population dropped to approximately 3,500 birds by 2007, which caused it to be protected under the Endangered Species Act in 2010.
Like other endemic Kaua‘i birds, long-term survival of ‘Akeke‘e depends on preservation of large tracts of native forest – particularly ‘ohi‘a. As with other native forest birds, vigilance is essential to prevent additional introductions of noxious plants, potential predators, and alien birds. The ʻAkekeʻe is threatened by the introduction of plants like the banana pōka that displace native plants. Feral pigs, goats, and deer also destroy native growth. Eventually, the insects on which the ʻAkekeʻe feeds will disappear from such areas, as they on longer find their usual host plants.
Natural hurricanes, as well as human development in the Koke‘e region reduces the amount of habitat available and increases breeding sites for mosquitoes. The spread of disease-carrying mosquitoes into native forests probably poses the greatest long-term threat to their survival. This is the reason why these birds are rarely found at lower altitudes, but only in higher, cooler regions where mosquitos do not occur. Efforts to prevent further habitat degradation will probably be most effective in maintaining this species.
Hawaiian Birds – Akekee
The ‘Akeke‘e is a small green and yellow bird found only in the mountains of Kaua‘i in the Hawaiian Archipelago. This Hawaiian honeycreeper lives above 3,250 feet elevation in native forests of the Alakaʻi Wilderness Preserve, Kōkeʻe State Park, and Waimea Canyon State Park.
Both sexes are greenish above, with yellow below, yellow cap and rump, and the female being slightly duller than the male. It is distinguished from other honeycreepers by its broad triangular face mask, long, notched tail, and conical bill. The bill is bluish gray, with the tip of lower mandible curved to one side. The active ʻAkekeʻe forages mostly in the native ‘ohi’a tree, and uses its unusual bill like scissors to cut open leaf and flower buds in search of insects to eat. This methodical probing is distinctive and helps identify it from a distance.
This Hawaiian honeycreeper was considered common in the late 1800s and into the early 1960s. The ‘akeke‘e population appeared to be relatively stable, even while other endemic Kaua‘i birds were sharply declining, and its population was estimated to be nearly 8,000 birds in 2000. However, the population dropped to approximately 3,500 birds by 2007, and is estimated to occupy only 10 to 12 percent of its original range. The ‘Akeke‘e (Loxops caeruleirostris) is now protected (2010) under the Endangered Species Act along with the ‘Akikiki. These two species join 33 other bird species listed as endangered and another listed as threatened in Hawai‘i. Photo by Jack Jeffrey.
Hawaiian Birds – Akikiki Breeding
The `Akikiki, a Hawaiian honeycreeper endemic to the island of Kaua‘i, builds a simple open-cup nest between March and May. The nest is composed primarily of a moss exterior and a lining of strips of ‘ohi’a bark, plant rootlets, and other fine plant fibers. Using materials gathered from live ‘öhi‘a trees, and constructing their nests in ‘öhi‘a trees, camouflages their nests making them difficult to detect.
Both male and female participate in nest construction with the male remaining close to the female, occasionally feeding her. Their short, straight, bifurcated tongue is well designed for extraction of insects, insect larvae, caterpillars, and spiders from crevices in bark. May brings a clutch of one to two eggs, followed by incubation (16-18 days) and nestling period (17-19 days), and the female ‘Akikiki exhibiting strong fidelity to the nest.
Juveniles have pale spectacles, fluffy plumage, and make distinctive begging call. When being fed, young ‘Akikiki typically perch on a branch lower than adult, quivers its wings and gapes while calling. Juveniles make a staccato d-d-d-d-dit call, while adults make several types of calls including a quiet cheep call and a distinct whit call. The song is a short, moderately descending trill that softens at the end, and presumably made only by male. Many Hawaiian honeycreepers also have a quiet vocalization, or whisper song. The whisper song of ‘Akikiki is an elaborate series of chips, cheeps, whinnies, squeaks, jumbled primary song, and mimicry of the calls of other species. Photo by Jim Denny.
Hear the `Akikiki produced by SoundsHawaiian
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