Elepaio

Chasiempis sandwichensis

Eric Vanderwerf
  • MONARCHINAE
  • 237,000

Elepaio has recently been split into three different species. Active and feisty, these little wren-like flycatchers are found on three of the Hawaiian Islands--Hawaii, Kauai, and Oahu--where they are unusual among Hawaii's native birds in being able to persist in disturbed forests with introduced plants. Populations remain fairly healthy, except on Oahu where they have seriously declined in recent decades; thus, the Oahu Elepaio is listed as endangered, both by IUCN and the U.S. Fish and Wildlife Service.  Neither Hawaii Elepaio nor Kauai Elepaio is federally listed, but both are listed internationally by IUCN as vulnerable.

Identification

This species has recently been split into three species (Chasiempis sandwichensis has been split into C. sandwichensis, C. sclateri and C. ibidis following AOU (2010).), each occupying a separate Hawaiian island - Hawaii, Kauai, and Oahu.  'Elepaio vary considerably in plumage coloration, and to a lesser degree in vocalizations, between the three currently recognized species. Identification is readily based on the discrete ranges of the three species. On the island of Hawaii, where three subspecies occur, the ranges are separated by unforested alpine areas and recent lava flows. In general 'Elepaio are recognized by their long cocked-up tails; vivid and complex patterns of brown, black, white, and rufous; and presence of two white wing bars. Their song is a loudly whistled version of the Hawaiian name e-le-PAI-o.

Distribution and Population Trends
It is thought that these species originally inhabited most forested areas from sea level to tree line on Hawaii, Kauai, and Oahu. Although much of their original range has been greatly reduced by clearing for development and agriculture, the broad habitat requirements and flexible foraging strategies of this species have kept them common while other native birds have declined dramatically or disappeared altogether. 'Elepaio are still fairly common and widespread on Hawaii and Kauai, especially in forested areas at higher elevations, but the situation on Oahu has deteriorated significantly. There the population survives in 7-8 small fragments, with the total population estimated at less than 2,000 birds.

Ecology

During an extended nesting season, 'Elepaio construct cup-like nests among the branches of any of a wide variety of trees, including both native and introduced species. Nesting dates range from January to August depending on the population, and even between years (perhaps in response to rainfall). While they forage on the wing in typical flycatcher fashion, 'Elepaio also spend time in trees and on the ground searching energetically through leaf litter for arthropods. They are highly versatile in their selection of foraging strategies and niches.

Threats
As with other native Hawaiian birds, the spread of avian malaria and pox by introduced mosquitoes, and clearing of habitat have had significant negative impacts on 'Elepaio populations. In many areas 'Elepaio persist due to their flexible habitat requirements, or else they have contracted their range to higher elevations. It's thought that the ground feeding habits of this species make them more susceptible to predation by feral cats and Indian Mongooses (Herpestes auropunctatus), while rats have been implicated in nest failures. On Oahu, adult survival has been shown to be lower than in a large population on Hawaii largely due to avian poxvirus transmitted by mosquitoes. Black rats have been implicated as the major factor causing a higher rate of nest loss on Oahu as compared to Hawaii. Storm events and heavy rainfall are natural phenomena that significantly impact nesting success, as evidenced by a study on Hawaii in which all 'Elepaio nests failed after a 3-day storm.

Conservation

The Oahu 'Elepaio (C. ibidis) is federally listed as Endangered. Measures currently being taken include active monitoring of populations and screening for disease resistance, in part to learn more about the dynamic between bird populations and disease vectors. A program of experimentally controlling introduced Black Rats on Oahu has been successful at increasing reproductive success. The Hawaii Department of Land and Natural Resources continues its efforts at predator control to decrease nest loss and increase populations of Oahu 'Elepaio.  On Hawaii, the Hakalau Forest National Wildlife Refuge supports a relatively large population of 'Elepaio, where it is listed internationally as vulnerable . On Mauna Kea, removal of feral sheep and goats has allowed habitat regeneration which will eventually increase habitat available to the species.

What Can You Do?

U.S. National Wildlife Refuges provide essential habitat for 'Elepaio and a great number of other species throughout the U.S. and its territories.   Unfortunately, the refuge system is often under-funded during the U.S. government's budgeting process.

The Endangered Species Act has helped protect Oahu 'Elepaio and made it possible to learn critical information about its biology.  Audubon continues to work to ensure that this vital legislation is being used to protect our publicly-owned wildlife resources.  Check out http://policy.audubon.org/endangered-species-actto learn of the latest news about the Endangered Species Act and how you can help. To learn more about other species protected under this legislation, visit: http://endangered.fws.gov/

Join Hawaii Audubon Society. A chapter of National Audubon, the Hawaii Audubon Society works to protect and educate people about Hawaii's birds. For more information visit http://www.hawaiiaudubon.com/

Support efforts to control feral animals and invasive plants and insects throughout the Hawaiian Islands. . For more information visit: http://www.hear.org/

Support efforts to protect native forest habitat on Hawaii, Kauai, and Oahu by state and federal agencies and conservation organizations.

References

Birdlife International, 2011. Datazone species factsheets.  http://www.birdlife.org/datazone/speciesfactsheet.php?id=32696

http://www.birdlife.org/datazone/speciesfactsheet.php?id=32698

http://www.birdlife.org/datazone/speciesfactsheet.php?id=32698

BirdLife International. 2000. Threatened Birds of theWorld. Lynx Edicions and BirdLife International, Barcelona and Cambridge, UK:

Culliney, J. L. 1988. Islands in a Far Sea: Nature and Man in Hawaii. Sierra Club Books, San Francisco.

Pratt, H.D., P. L. Bruner, and D. G. Berrett.  1987. The Birds of Hawaii and the Tropical Pacific.  Princeton University Press, Princeton, NJ.

Vanderwerf, E. A. 1998. 'Elepaio (Chasiempis sandwichensis). In The Birds of North America, No. 344 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologist's Union, Washington, D.C.