Hawaiian Goose

Branta sandvicensis

U.S. Fish & Wildlife Service
  • ANATIDAE
  • Swans, Geese, Ducks
  • 625

Unique in the goose family, this Hawaiian endemic has deeply furrowed golden neck plumage and is largely terrestrial, spending little time on the water. After a close call with extinction, it remains as Hawaii's state bird. It is one of the most isolated, sedentary, and threatened of all water birds. Hunting, poaching and egg collecting took a heavy toll through the early 1900's. Despite tenacious re-introduction efforts beginning in the 1960's, the population still has not recuperated to a self sustaining condition.

Identification
Its extremely restricted range (the smallest of any living goose) and remarkably furrowed neck plumage make this goose unmistakable. It is of small stature with heavily barred plumage and the sexes look alike. It does not tend to associate with other geese. It is one of the few species that actually evolved in Hawaii and differs from true geese by having longer legs, reduced webbing between its toes, and a more erect posture - all presumably adaptations to a more terrestrial lifestyle. In addition, it has much smaller wings than those of its closest relative, the Canada Goose. Its calls are similar to those of the Canada Goose.

Distribution and Population Trends
Wild populations are now found only on the islands of Hawaii, Maui (where reintroduced), and Kauai (where reintroduced). Formerly it was found on most of the larger Hawaiian islands. This species ranges from coastal to subalpine elevations and has a population of 960 to 1,000 individuals. In 1918 after the population was estimated at no more than 30 individuals left on Hawaii, a captive breeding program was set up on the island, with a sister program underway in England by the mid 1950's. Although it has grown, the population is by no means stable. Kauai Island has abundant grasses and is still mongoose-free, and it follows that the population is growing there the most rapidly. High elevation habitats on the other islands support very few birds due to food shortages. Years with higher rainfall in these areas consistently show better survival rates, but even so, they must be periodically re-stocked with new individuals. In addition, the National Park runs a supplemental feeding program to get them through periodic food shortages. Prior to intense depredation pressures, the Hawaiian Goose nested in the leeward lowlands, where winter rains caused fresh green growth of native plants. Generally speaking, the success of this species is limited by food shortages in the upper elevations, and predation in the lowlands.

Ecology
An herbivore, the Hawaiian Goose grazes and browses leaves, flowers, berries and seeds from grasses and shrubs. It inhabits shrub and grasslands as well as habitat modified by humans. In response to depredation pressures, it is now primarily found breeding on the rugged slopes of volcanoes, often choosing to nest under sparse bushes in the middle of barren lava fields. The introduced population on Kauai also apparently now breeds in the lowlands, in areas where introduced land predators have been removed. It lays relatively large eggs in small clutches over an extended nesting season (the longest of any wild goose, from August to April), and has a low reproductive rate.

Threats
Invasive alien plant species are choking out native plants over much of its preferred habitat, in many cases leaving unfavorable foraging conditions. At higher elevations, more native plants dominate, but the food density is low and shortages pose a serious problem for this species, even in years of good rainfall and abundance. Mongoose and feral cats take a toll on the young, which remain flightless for their first 11 to 14 weeks. Roadside mowing attracts the geese to the grass and road casualties are the cause of most adult deaths. Poaching continues to pose a minor problem. The population is continually re-stocked with captive-bred young from England, which may carry parasites.

Conservation
The Hawaiian Goose is listed as Endangered both by the U.S. Fish & Wildlife Service, and in the IUCN's Red Databook. Historically, this species has been hunted, eggs have been eaten and goslings domesticated, for trade with passing ships. Currently, domestication is used only for purposes of captive breeding and re-introduction. Hunting was officially banned in 1907, but occasional poaching still occurs. Since 1960, more than 2,300 individuals have been released, but survival rates have been poor and the population still cannot sustain itself. During the drier years, individuals leave their high elevation sanctuaries in search of the greener lowland pastures, where mortality from predation and human-induced threats is much higher. Management of vegetation is required to meet nutritional needs. On Kauai, the only large island without mongoose, the population is actually growing, providing a sound case for eradication of this introduced predator on the other islands. Birdlife International recommends establishing large, predator-free reserves in lowland habitat rich in food resources.

What Can You Do?
The Endangered Species Act has helped protect the Hawaiian Goose 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/ to 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/

U.S. National Wildlife Refuges provide essential habitat for the Hawaiian Goose, 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. To support  U.S. National Wildlife Refuges, consider purchasing a duck stamp which helps to fund wetland habitats in refuges: http://www.fws.gov/duckstamps/

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.audubon.org/chapters/hawaii-audubon-society .

References
Birdlife International. 2000. Threatened Birds of the World. Lynx Edicions, Barcelona.

BirdLife International (2006) Species factsheet: Branta sandvicensis, Hawaiian Goose http://www.birdlife.org/datazone/speciesfactsheet.php?id=383

Banko, P., J. M. Black, and W. E. Banko. 1999. Hawaiian Goose (Nene) (Branta sandvicensis). In The Birds of North America, No. 434 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D. C.

Ehrlich, P.R., Dobkin, D.S., and D. Wheye. 1992. Birds in Jeopardy. Stanford University, Stanford, CA.

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

Shallenberger. R.J. 1984. Hawaii's Birds. Hawaii Audubon Society, Honolulu, HA.