The Hawaiian Goose

The Hawaiian Goose, or Nene, is the subject of intense conservation efforts.

Nene

When the Hawaiian Islands emerged from the sea, one by one, as a series of volcanic mountains, they were empty and barren. The only life that could reach them were windborne plant seeds and animals that could fly or raft here on floating mats of vegetation. These species adapted to the new environment, and evolved into some of the most unique and rare ecosystems in the world.

About half a million years ago, a flock of Canadian Geese (Branta canadensis) somehow became stranded on the islands. Perhaps they were caught in a storm and blown off course. Compared to their ancestral Canadian home, the islands, which included the newly-emerged “big island” of Hawaii, were a tropical paradise, with abundant food and few predators. Over time, the introduced geese population thrived, and as it adapted to its new home it split into two species. One of these became the much larger (but now extinct) Hawaiian Giant Goose. The other became smaller (a common phenomenon known as “island dwarfism”) and is now known as the Hawaiian Goose or Nene. Today only the Nene (Branta sandvicensis) survives.

The Nene looks similar to the Canadian Goose, but is noticeably smaller, and has tan-colored check patches and a tan neck. It makes many of the same honking sounds as its Canadian ancestor, but also a distinctive “nay-nay” call, from which it gets its name.  Because its Hawaiian environment had few predators, the Nene has mostly given up flight, and instead has evolved longer legs and feet that are only partly webbed, allowing it to walk and run on the ground.

Like all geese, the Nene is herbivorous, and grazes on grasses, leaves, flowers, and sometimes soft fruits. However unlike most geese, which are aquatic, the Nene prefers to live inland on the islands, where it grazes in grasslands and old lava flows. In modern times, they are commonly seen on golf courses.

The geese breed almost year-round, avoiding only the heat of summer. Nests are made with rocks on bare lava fields, where the female will lay 3-5 eggs while the male watches over her. Since there are few predators to attack them, the females go into a sort of hypnotic trance while incubating the eggs for around 30 days.  The newly-hatched goslings are capable of running and feeding themselves, and stay near their patents until the next nesting season.

At one time the Nene inhabited virtually every one of the Hawaiian Islands, with an estimated 25-30,000 individual birds. When Native Hawaiians arrived, they hunted the geese for food, but seem to have had only a minor impact.

The real trouble began when Europeans arrived. The first of these was the British explorer Captain James Cook in 1778. Not only did the Europeans hunt the geese relentlessly, but they brought (intentionally or unintentionally) nonnative predators such as cats, mongooses, rats, and pigs. These attacked the nestlings and eggs, and the Nene, who had evolved in the absence of ground predators, had no way to defend against the onslaught. Populations declined and the islands became depopulated. By 1890, there were only remnant populations left on the larger islands. In 1949, researchers were only able to find 30 individuals remaining.

Because the Nene is the State Bird of Hawaii, officials took a special interest in preserving the species, and a program of captive breeding was begun. Protected areas were established at Volcanoes National Park, Haleakala National Park and the Maui Bird Conservation Center. Small flocks were also dispersed to zoos and conservation centers around the world, who began captive-breeding of their own. Wild populations were re-established in the Kilauea Point and Hakalau Forest National Wildlife Refuges, and in 2003 a program was established on Molokai to encourage private ranchers and landowners to set aside habitat for reintroduced Nene. In 2014 a pair of Nene were established in the James Campbell National Wildlife Refuge on Oahu.

Today there are around 4,000 Nene, with about half of these in the wild. Self-sustaining breeding populations have been established in the wild on the islands of Hawaii, Maui, Molokai and Kauai.

Post a Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s