Nene-nui
Encyclopedia
The Nēnē-nui or Woodwalking Goose (translation of Branta hylobadistes) is an extinct species of goose
that once inhabited Maui
and possibly (or closely related species) Kauai
, Oahu
and perhaps Molokai
in the Hawaiian Islands
. It is known from a large number of subfossil
bones (several thousand bones from many dozens of individuals) found in holocene
cave sediments.
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 nēnē are similar in that they have the sides and front of their necks buff-colored with dark furrows http://news.nationalgeographic.com/news/2002/02/0206_020206_canadiangeese.html. 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 led to the goose's change in wingspan and change in the depth of their skulls and bills.
Of course, the appearance of the Nēnē-nui in life is unknown, but it can be assumed to have been similar to its extant relative, as the Branta geese share most plumage characteristics. The chief differences to the Nēnē were that it was usually about 5% larger, while the bones of the flight apparatus were reduced in length by about the same amount. There was, however, much variation in size of the wing bones and the bird itself; some small specimens had much reduced wings.
At the time of its extinction, the Nēnē-nui was in an intermediary stage of the evolution towards flightlessness: the extensive material suggests that that, in the same population, the entire span of individuals with diminished or marginal flight capacity to flightless individuals with markedly reduced wings had been present. Thus far, the Nēnē-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 can be conjectured that the reproductive isolation between the Nēnē-nui and the Nēnē was not entirely complete, allowing for the introgression of Nēnē alleles (the surviving species still is a strong flyer, but no longer capable of long-range migration) and sustaining the intermediate state for longer than usual.
A single skeleton of a similar bird has been found on Kauai, and many more on Oahu; the latter seem to be intermediate between the Nēnē-nui and the Nēnē. As the relationships of these forms have not been determined, they are not formally assigned to B. hylobadistes. No material of this species has been found on Molokai; however, the locations where extinct bird bones have been found on that island are in the arid
zone and hence it would be unlikely to expect bones of a waterfowl to turn up in such locations.
period), the Nēnē-nui (as well as most of its relatives and the local ducks, such as the Moa-nalo
s) became extinct soon after the human settlement of the Hawaiian Islands; by the end of the first millennium AD, it had almost certainly disappeared.
Goose
The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....
that once inhabited Maui
Maui
The island of Maui is the second-largest of the Hawaiian Islands at and is the 17th largest island in the United States. Maui is part of the state of Hawaii and is the largest of Maui County's four islands, bigger than Lānai, Kahoolawe, and Molokai. In 2010, Maui had a population of 144,444,...
and possibly (or closely related species) Kauai
Kauai
Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
, Oahu
Oahu
Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
and perhaps Molokai
Molokai
Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...
in the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. It is known from a large number of subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
bones (several thousand bones from many dozens of individuals) found in holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
cave sediments.
Evolution
The Nēnē-nui (along with the endangered Nēnē and the extinct Giant Hawaii Goose) evolved from the Canada GooseCanada Goose
The Canada Goose is a wild goose belonging to the genus Branta, which is native to arctic and temperate regions of North America, having a black head and neck, white patches on the face, and a brownish-gray body....
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 nēnē are similar in that they have the sides and front of their necks buff-colored with dark furrows http://news.nationalgeographic.com/news/2002/02/0206_020206_canadiangeese.html. 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 led to the goose's change in wingspan and change in the depth of their skulls and bills.
Of course, the appearance of the Nēnē-nui in life is unknown, but it can be assumed to have been similar to its extant relative, as the Branta geese share most plumage characteristics. The chief differences to the Nēnē were that it was usually about 5% larger, while the bones of the flight apparatus were reduced in length by about the same amount. There was, however, much variation in size of the wing bones and the bird itself; some small specimens had much reduced wings.
At the time of its extinction, the Nēnē-nui was in an intermediary stage of the evolution towards flightlessness: the extensive material suggests that that, in the same population, the entire span of individuals with diminished or marginal flight capacity to flightless individuals with markedly reduced wings had been present. Thus far, the Nēnē-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 can be conjectured that the reproductive isolation between the Nēnē-nui and the Nēnē was not entirely complete, allowing for the introgression of Nēnē alleles (the surviving species still is a strong flyer, but no longer capable of long-range migration) and sustaining the intermediate state for longer than usual.
A single skeleton of a similar bird has been found on Kauai, and many more on Oahu; the latter seem to be intermediate between the Nēnē-nui and the Nēnē. As the relationships of these forms have not been determined, they are not formally assigned to B. hylobadistes. No material of this species has been found on Molokai; however, the locations where extinct bird bones have been found on that island are in the arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
zone and hence it would be unlikely to expect bones of a waterfowl to turn up in such locations.
Extinction
In a manner similar to that which occurred on other Pacific islands during the time (the HoloceneHolocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
period), the Nēnē-nui (as well as most of its relatives and the local ducks, such as the Moa-nalo
Moa-nalo
The moa-nalo are a group of extinct aberrant, goose-like ducks that lived on the larger Hawaiian Islands, except Hawaii itself, in the Pacific...
s) became extinct soon after the human settlement of the Hawaiian Islands; by the end of the first millennium AD, it had almost certainly disappeared.