The nēnē-nui was larger than the nene, varied from flightless to flighted depending on the individual, and inhabited the island of Maui.

It is believed that the herbivorous giant Hawaiʻi goose occupied the same ecological niche as the goose-like ducks known as moa-nalo, which were not present on the Big Island.

Goslings resemble adults, but are a duller brown and with less demarcation between the colors of the head and neck, and striping and barring effects are much reduced.

The nene is an inhabitant of shrubland, grassland, coastal dunes, and lava plains, and related anthropogenic habitats such as pasture and golf courses from sea level to as much as 2,400 m (7,900 ft).

[14] The nene could at one time be found on the islands of Hawaiʻi, Maui, Kahoʻolawe, Lānaʻi, Molokaʻi, Oʻahu and Kauaʻi.

A pair arrived at the James Campbell National Wildlife Refuge on Oʻahu in January 2014; two of their offspring survived and are seen regularly on the nearby golf courses at Turtle Bay Resort.

The breeding season of the nene, from August to April, is longer than that of any other goose;[15] most eggs are laid between November and January.

[16] It is believed that it was once common, with approximately 25,000 Hawaiian geese living in Hawaiʻi when Captain James Cook arrived in 1778.

[12] Hunting and introduced predators, such as small Indian mongooses, pigs, and feral cats, reduced the population to 30 birds by 1952.

Under the direction of conservationist Peter Scott, it was bred back from the brink of extinction during the 1950s for later re-introduction into the wild in Hawaiʻi.