The Hawaiian goose - also known locally as "nene", is the rarest goose in the world. This goose is a little different from other geese because of its sedentary life. It does not undergo harsh weather. Its wings are not strong because it does not migrate, in fact, it does not fly outside Hawaii. As it hardly ever swims, its feet are just partially webbed. Instead, its toes and legs are longer than those of other species, which enables it to climb over the rocky terrain of Hawaii and to walk without waddling, as geese typically do.
Native to the Hawaiian Islands, the Hawaiian goose today is most found most commonly on Hawaii, in and around the Hawaii Volcanoes National Park, and on Maui in Haleakala National Park. A large and increasing population also lives on Kauai Island, and the animal has recently been reintroduced on Molokai Island. They inhabit a range of habitats, including scrub forests, grasslands and volcanic slopes with sparse vegetation.
Hawaiian geese are diurnal. They sleep on the ground, their feet tucked under their bodies. The immediate family: a mating pair with their children, is the most tightly-knit social unit. Hawaiian geese may live in flocks of as many as 30 birds, some groups being more loosely formed than others, with nests from as close by as 45 meters to some very far away. Dominance ranking depends on the family unit’s size. Males defend against other geese the territory that immediately surrounds their nests and families. Their wings being 16% smaller than those of the Canada goose, their closest relative, they are not very good fliers. However, they fly from one island to another, usually taking off from the land. They do swim, mostly in ponds and lakes. They spread oil, using their beak, from their oil gland onto their feathers to waterproof them.
Hawaiian geese are monogamous, forming life-long pair bonds. From August through April is the breeding season, peaking from October to March. These birds nest in solitary pairs and the nest is built by the female, being a shallow scrape in the ground, lined with vegetation and down, usually sheltered by tussock grass or rock. The same site is often reused year after year by the same pair. 2-5 creamy white eggs are laid, and the female incubates them for about one month. The goslings are precocial and can feed themselves, but usually remain with their parents for one year. They fledge at around 10-12 weeks old, and around 2-3 years old they are sexually mature.
The main threat to Hawaiian geese is lack of a suitable habitat, as well as introduced species such as mongooses, and feral cats and dogs, which prey on young birds and eggs. Disease transmission and inbreeding depression may also be threats for captive-reared birds.
According to the IUCN Red List, the total population size of the Hawaiian goose is 2,500 individuals, including 250-999 mature individuals. This species is classified as vulnerable, but its numbers are increasing today.
Hawaiian geese are important for spreading seeds for a great number of the plants that they eat. They are also important as a source of food for many of the animals that are their natural predators.