WatchList Species Account for Nene or Hawaiian Goose |
the list as a Red List Species
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.