Females have a mass of , while males average , 11% larger than females. Adult males have a black head and hindneck, buff cheeks and heavily furrowed neck. The neck has black and white diagonal stripes. Aside from being smaller, the female Nene is similar to the male in colouration. The adult's bill, legs and feet are black. It has soft feathers under its chin. Goslings resemble the male, 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 . Some populations migrated between lowland breeding grounds and montane foraging areas. The nene could at one time be found on the islands of Hawaii, Maui, Kahoolawe, Lānai, Molokai, Oʻahu and Kauai. Today, its range is restricted to Hawaii, Maui, Molokai, and Kauai. 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; most eggs are laid between November and January. Unlike most other waterfowl, the nene mates on land. Nests are built by females on a site of her choosing, in which one to five eggs are laid (average is three on Maui and Hawaii, four on Kauai). Females incubate the eggs for 29 to 32 days, while the male acts as a sentry. Goslings are precocial, able to feed on their own; they remain with their parents until the following breeding season. The nene is a herbivore that will either graze or browse, depending on the availability of vegetation. Food items include the leaves, seeds, fruit, and flowers of grasses and shrubs. The nene is the world's rarest goose. It is believed that it was once common, with approximately 25,000 Hawaiian geese living in Hawaii when Captain James Cook arrived in 1778. Hunting and introduced predators, such as small Asian mongooses, pigs, and cats, reduced the population to 30 birds by 1952.