The Nene-nui (Great Nene or Woodwalking), Branta hylobadistes, is an extinct species of goose that once inhabited Maui and possibly Kauai, Oahu and perhaps Molokai in the Hawaiian Islands. It is known from a large number of sub fossil bones (several thousand bones from many dozens of individuals) found in Holocene cave sediments.

The Nene-nui evolved from the Canada Goose which migrated to the islands half a million years ago and adapted to the Pacific’s tropical environment. This evolution is evidenced from both genetic similarities and outward appearances. An example of this is that Canada Geese have black necks, whereas the surviving Nene are similar in that they have the sides and front of their necks beige colored with dark furrows. Scientists have also concluded that the two major reasons for this evolution were the loss of migration as well as the change in habitat, which eventually lead to the goose’s change in wingspan and change in the depth of their skulls and bills.

At the time of its extinction, the Nene-nui was in an intermediary stage of the evolution towards becoming flightless. Thus far, the Nene-nui is the only species in which the process of becoming flightless is documented by actual paleontological evidence, rather than just the end result. It became extinct soon after the human settlement of the Hawaiʻian Islands. By the end of the first millennium AD, it had almost certainly disappeared.