Goose, Hawaiian

Branta sandvicensis

phylum: Chordata

class: Aves

order: Anseriformes

family: Anatidae

status: Vulnerable, IUCN Endangered, ESA

range: USA (Hawaii)

Description and biology

The Hawaiian goose or nene (pronounced NAY-nay) is uniquely colored. Its gray-brown feathers have white tips that form widely spaced bars on the bird's back. On its underside, the bars are closer together. The sides of the nene's neck are reddish-brown with black and white markings. The bill, face, cap, and back of the neck are all black.

An average nene measures 22 to 30 inches (56 to 76 centimeters) long and weighs between 4 and 5 pounds (1.8 and 2.8 kilograms). The bird has excellent senses of hearing and sight. It also has strong legs and wings. It feeds mainly on vegetation, including grasses, leaves, herbs, and berries.

The breeding season for Hawaiian geese begins in October or November and extends through February. Male-female pairs (a male is known as a gander, a female as a goose) build nests on the ground, usually in a patch of vegetation. The female lays 3 to 5 eggs. Both the gander and

goose incubate (sit on or brood) the eggs for about 30 days until they hatch. The goslings fledge (develop flying feathers) in 10 to 12 weeks.

Habitat and current distribution

Hawaiian geese are found on the island of Hawaii. A small population of the birds has been reintroduced to the island of Maui. Two more populations have recently established themselves on the island of Kauai. In 1997, biologists (people who study living organisms) estimated that 890 nenes existed in the wild: 375 on Hawaii, 250 on Maui, and 265 on Kauai.

Nenes breed at elevations between 5,000 and 8,000 feet (1,524 and 2,438 meters). Water is not often plentiful at those heights, but the birds can survive for long periods of time by feeding on plants that contain a high amount of water.

History and conservation measures

Before 1800, the Hawaiian goose was common throughout the islands of Hawaii and Maui. Its population at that time has been estimated at 25,000. Although native inhabitants of the islands had hunted the bird for centuries, its population remained stable. That soon changed in the nineteenth century with the arrival of European settlers. They hunted the bird mercilessly and also introduced predators of the nene. These cats, dogs, rats, and mongooses preyed on the bird's eggs and on the young goslings. By 1900, the nene existed only at high altitudes in remote areas on Hawaii. It was extinct on Maui.

As more people began inhabiting Hawaii in the twentieth century, the nene's habitat and food sources were reduced. By 1952, only 30 birds survived.

In 1949, scientists started a captive-breeding program for the Hawaiian goose. The birds bred and raised in captivity were eventually reintroduced on Maui and Hawaii. In 1982, a hurricane destroyed cages containing captive nenes in Kauai. They escaped to the wild and fared quite well on the island. The reintroduced birds have survived well in all the locations in Hawaii, but have not bred in the wild as well as scientists had hoped. Because of this, scientists have had to keep adding captive-bred nenes to the wild population.