The Plight of the Nēnē

How the Hawaiian goose went from thriving to near extinction and now recovery

Dec 2, 2022

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A black and white rendering of a very large goose. It has a dark colored neck and striped feathers. Leaves are on the ground and there is what appears to be a tree stump in the background. — Extinct giant nēnē rendering based on fossil remains discovered in 1926 beneath a prehistoric lava flow on Hawai‘i. The giant nēnē was about twice as large as today’s nēnē.

500,000 Years Ago Canada Goose Ancestors Blew off Course

Before Polynesians settled Hawai‘i over a millennia ago, three unique species of geese thrived in Hawai‘i— nēnē (Branta sandvicensi), nēnē nui (Branta hylobadistes), and the giant nēnē (Branta rhuax). All three were descendants of Canada goose ancestors, which arrived in Hawai‘i approximately 500,000 years ago.

Little is known about the prehistoric giant nēnē but fossil records show that the nēnē nui went extinct shortly after humans settled the islands. Humans hunted them for food and brought in predators including rats and dogs who preyed on the birds and their eggs.

The faster and more agile nēnē escaped the tragic fate of their larger cousins.

Even in the early 19^th century they still flourished on nearly all the Hawaiian Islands. On Hawai‘i Island alone there were an estimated 25,000 nēnē!

A New Wave of Threats Arrived

Europeans arrived in the late 18^th century. Nēnē were hunted to feed whaling ships and new settlers. During the plantation era in the 19^th and 20^thcenturies huge swaths of habitat were destroyed and more predators including mongoose were introduced. By 1950 the nēnē population had collapsed with less than 30 nēnē estimated to be living in the wild, all on Hawai‘i Island.

Captive-breeding programs breed nēnē from private collections in Europe, Hawai‘i and the mainland United States in effort to recover the nēnē population. Between 1960 and 1997 over 2,000 nēnē were released on Hawai‘i and Maui. Reintroduction efforts were met with mixed results. Introduced predators, especially mongoose killed many of the newly released nēnē and their offspring.

Kaua‘i Held off on Reintroduction

Conservation biologists did not immediately reintroduce nēnē to Kaua‘i because there was no known history of nēnē nesting on the island. That was until research at Makauwahi Cave Reserve on the south shore of the island exposed deeply buried nēnē bones. The discovery finally provided the necessary evidence to begin planning for reintroduction on Kaua‘i.

The first release of a dozen young captive-reared birds took place at Kīlauea Point National Wildlife Refuge in 1991. Reintroduction efforts continued through 2000.

Three Nēnē, or Hawaiian goose standing side by side, look in unison to the left side of the frame amid the wetlands grass in Kaua'i. They are framed by two Hawaiian geese looking outwards on either side of them. — Nēnē photographed at Hanalei National Wildlife Refuge during the 2022 annual statewide nēnē count. There were 2430 nēnē counted on Kaua‘i and 3862 statewide.

A Conservation Success Story

With no established mongoose population, nēnē thrived on Kaua‘i and helped bring up the state population numbers. By 2012 Kaua‘i accounted for an estimated 60% of Hawaii’s statewide nēnē population.

In 2019 the nēnē population was estimated at 3,252 and the species was Federally down-listed from endangered to threatened. While this did remove some of the protections guaranteed by the Endangered Species Act, conservation efforts continue throughout Hawai‘i and Kaua‘i. Kīlauea Point National Wildlife Refuge leads several of those efforts.

The 2022 annual nēnē population survey estimated 3,862 statewide with 2,430 of those birds on Kaua‘i.