NENE (Branta sandvicensis) – (See images below)
DESCRIPTION: The Nēnē is a medium size goose with a black head, nape and bill, and oblique black and white furrows on the neck, with the white predominant at both ends. The breast is grey and the under parts finely barred with grey. The back is darker grey with the feathers edged in white. The tail is dark grey and the rump is white. The legs and feet are black. Sexes are similar. The bird is around 25 inches (63 cm) long. The bird is sedentary but can fly well enough within the same island.
NAME: The Nēnē (or Hawaiian Goose) derives it Hawaiian name from its soft call. The Latin genus name ‘Branta’ comes from Old English and Old Norse and means ‘burnt’, in reference to the dark plumage of the bird. The Latin species name ‘sandvicensis’ refers to the former name of the Hawaiian Islands, the Sandwich Islands.
HABITAT: Can vary from lowlands with thick vegetation to scrubland, grass fields and golf courses. Nēnēs frequent more lava fields with sparse vegetation than wetlands, so their feet evolved accordingly and are only partially webbed.
DIET: Plant material such as seeds, leaves, berries, flowers.
NESTING: Nēnēs are monogamous and mate for life. They breed most of the year but winter is the peak mating season. The nest is built under thick vegetation and lined with down. About 3-4 white eggs are laid. Goslings can’t fly until three months old.
DISTRIBUTION: Endemic to Hawaii and found only on Kauai, Maui and the Big Island. Bred in zoos around the world.
CONSERVATION: The nēnē is the world’s rarest goose, having gone down to a population of only 30 in 1952. However this bird breeds well in captivity and there are now around 1,000 individuals in zoos around the world. Thanks to conservation efforts, the wild population has rebounded to around 800 birds. But the nēnē is still vulnerable to introduced feral predators such as mongoose, pigs and cats, because it nests on the ground. There is also mortality from road accidents (hence the signs seen below), as they’re the same color as the road and walk slowly, and often some of their habitat is foggy so they’re hard to see.
NOTES: The nēnē is endemic to Hawaii, and it is the state bird. DNA analysis has shown that the nēnē evolved from the Canada goose over hundreds of thousands of years. (There are still some Canada geese that will show up in Hawaii during their yearly migration.) At some point in the past, there was also the giant nēnē, but it is now extinct.
Fact sheet from Hawaii Department of Land and Natural Resources: Nene – Hawaii DLNR – Oct. 2005

The Nene is the State Bird of Hawaii - Honolulu Zoo
The Nene is the State Bird of Hawaii
Nene at the Honolulu Zoo
Nene at the Honolulu Zoo
Because of introduced predators, nene became almost extinct. Honolulu Zoo, Oahu
Nene became almost extinct
Nenes are still vulnerable and their numbers in the wild very low, so predator control is necessary. Honolulu Zoo, Oahu.
Controlling predators is necessary
The Nene descends from the Canada goose
Nenes descend from the Canada Goose
Nene looking up – Volcano Golf Course, Big Island, HI – © Denise Motard
Looking up, Volcano Golf Course
The Nene with the number 31 band on the Volcano Golf Course is "No. 831, a 9 year old male.  He hatched in Hawaii Volcanoes National Park, resides in the Volcano area year round, frequenting areas both within and adjacent to the park." This is the answer I got from USFWS, Pacific Islands Fish and Wildlife Office when I inquired about the bird band number.
Nene no. 831 – Volcano Golf Course, Hawaii Volcanoes National Park – © Denise Motard
Nene male No. 831, 9 years old
Nene no. 831 foraging – Volcano Golf Course, Big Island, HI – © Denise Motard
Nene No. 831 foraging, Volcano
Nene on Volcano Golf Course – Big Island, HI – © Denise Motard
No. 831 on Volcano Golf Course, HI
Nene crossing warning sign – End of Chain of Craters Road – HVNP, Big Island – © Denise Motard
Nene habitat, Hawaii Volcanoes NP
Nene crossing warning sign – Hawaii Volcanoes National Park, Big Island – © Denise Motard
Nene crossing