WatchList Species Account for Nene or Hawaiian Goose (Branta sandvicensis)

Qualifies for the list as a Red List Species

Photo: USFWS

Hawaii’s state bird, the endemic Hawaiian Goose is largely terrestrial and spends relatively little time on the water. A sedentary species with the most restricted range of any goose, it is also the only goose not occurring naturally in continental areas. During the early 1900s it declined considerably due to hunting, poaching, and egg collecting. The population is still not self-sustaining in spite of extensive reintroduction efforts which began in the 1960s. Formerly more widespread in the Hawaiian Islands, a population still exists on the island of Hawaii and reintroduced populations are found on Maui and Kauai. It is found from coastal areas to subalpine elevations.

In the early 20th Century, the population in the islands had dwindled to no more than 30 individuals; at that point a captive breeding program was set up, and later, a captive flock was established at Slimbridge in England. Its current population in the wild has grown to about 1,000 individuals, but the population is not stable; more than 2,300 individuals have been released into the wild since the 1960s, largely from England, but there is poor survival in the birds and the population requires constant restocking. During the drought years of 1976 to 1983, most of the released birds perished. Loss of adaptive skills may be a factor in limiting the success of released birds bred in captivity.

The higher elevations support very few birds due to food shortages, and to keep the birds alive the National Park Service must provide supplemental food to meet these shortages. Predation on the bird is heavy in the lowlands of Maui and Hawaii, predominantly due to the mongoose, though feral cats and dogs also attack and kill birds on the nest. In general, predation limits population size in the lowlands and food shortages at the higher elevations. In the lowlands poaching and road kills are responsible for much adult mortality on Hawaii. The Hawaiian Goose inhabits shrublands and grasslands as well as habitat modified by humans, such as golf courses. Like other geese a grazer and browser, it subsists on leaves, flowers, berries and seeds from grasses and shrubs. Its upright stance allows it to browse high for its food items, and its strong legs and padded toes allow it to move swiftly and surely over rugged terrain, such as lava fields at high elevations. Feral goats, sheep, and cattle reduce the amount of food available to the goose. Invasive alien plant species are choking out native plants over much of its preferred habitat, limiting food availability. Where native plants dominate, at higher elevations, food density is low, leading to periodic shortages.

Because of nest predation, the bird now breeds primarily on the slopes of volcanoes, often under bushes in the middle of lava fields. The best habitat for the bird, however, is thought to be pastureland. On Kauai, it breeds in lowland areas where predators have been removed. In contrast to other goose species, it has a low reproductive rate, with low clutch sizes and slow growth of goslings, which remain flightless for several weeks after hatching, during which they are easy prey for mongooses and feral cats. Hunting and taking of eggs had an impact on the population in the early 20th Century, but hunting has been banned since 1907. The bird does well under domestication, now used only for captive breeding and reintroduction. On Kauai, where the mongoose has never become established, the bird’s numbers are increasing, and on Maui, annual production exceeds mortality. As a conservation measure, predator-free reserves with abundant food resources should be established in lowland habitats.