Nene
Order: Anseriformes
Family: Anatidae
Genus/Species: Branta sandvicensis
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Photo by Jessie Cohen, NZP |
Description: Nene, or Hawaiian Geese, are medium sized gray brown geese that somewhat resemble small Canadian Geese. The face, cap, bill, and feet are black. The buff colored feathers of the neck are so heavily furrowed that the neck appears to have wavy black stripes. Their feet have much less webbing than those of most other waterfowl. Sexes are very similar in appearance, though the males are slightly larger. The native Hawaiian name, Nene, is derived from their distinctive "nay-nay" vocalization. The Nene is the official State Bird of Hawaii.
Distribution and Habitat: Nene
are found only in the Hawaiian islands. The wild population
was reduced in this century to two remnant populations on
the big island of Hawaii. Reintroduction is being attempted
in the Haleakala Crater area on Maui and a small population
that began with escaped birds is becoming established on Kauai.
Nene are unique among geese in that they are not normally
observed near water. The reduced webbing on their feet is
an adaptation to their rugged upland habitat. They inhabit
the rugged volcanic slopes of mountains such as Mauna Loa
and Mauna Kea, frequenting the small pockets of vegetation,
called kipukas, that grow between the lava flows.
Diet: Nene browse the sparse
vegetation found among the lava flows. They eat a wide variety
of leaves, fruits, buds, and seeds of the native plants. The
high altitude kipukas can be a very arid habitat. Much of
their water intake in these areas comes from consuming juicy
native berries. They have readily adapted to consume the fruits
of many of the introduced species of plants but they also
have to compete for these scarce resources with a variety
of introduced upland birds.
Reproduction: They build their
saucer-shaped nests in the concealment of the bushy pockets
of vegetation at altitudes between 5,000 and 8,000 feet. The
female incubates her eggs for 29-30 days, while the male stands
watch from a nearby vantage point. The young goslings grow
far more slowly than the more northern species of geese. It
may take them as long as three months to fledge. This extended
flightless period increases their vulnerability to a host
of introduced predators, most notably mongooses. The nests
may be trampled by foraging feral goats and pigs.
Conservation: The Nene has
been brought back from the brink of extinction through heroic
captive propagation efforts, but it is not yet self sustaining
in the wild. By 1949 a population that was once estimated
at 25,000 had been reduced to a mere 20-30 birds in the wild,
with another 17 in captivity. Extensive hunting, habitat loss,
introduced predators, competition for scarce food resources,
and degradation of habitat by introduced livestock all contributed
to the population crash. Fortunately aviculturists have learned
to propagate the species successfully in captivity. The wild
population is being continuously augmented with released captive
reared birds. Predator control programs are ongoing, and scientists
erect protective barriers around wild nests to protect them
from trampling. The various wild populations total perhaps
400 birds. There is evidence to suggest that the population
would once more begin to decline without the continuous recruitment
from the captive rearing program. What habitat remains for
the Nene may not be good enough to sustain the population
independently.
References:
Berger, A. J. 1981. Hawaiian Birdlife. University Press of Hawaii, Honolulu.
Ehrlich, P. R., Dobkin, D. S., and D. Wheye. 1992. Birds in Jeopardy. Stanford University Press, Stanford.
Kear, J. and A. J. Berger, 1970 . The Hawaiian Goose. Buteo Books,
Pratt, H. D., P. L. Bruner and D. G. Berrett. 1987. The Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, NJ.
Todd, F. S. 1996. Natural History of the Waterfowl. Ibis Publishing Co., San Diego, CA.
Please note: There are no longer any of these birds at the Zoo.
