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Two Anas species of flightless duck which are only found on two cold, bleak,
wet and windswept subantarctic islands, are another remarkable feature of the isolated
evolution of New Zealand ecology.
The Campbell Island teal Anas nesiotis and the Auckland Island teal A.
aucklandica are thought to have been isolated in New Zealand for a long time, and
consequently became flightless.
The related mainland brown teal A. chlorotis which is also endemic,
is a more recent arrival, about 10,000 years ago according to fossil records. It is
still a strong but reluctant flier, and is more closely related to the Australian chestnut
teal, which migrates but does not breed in New Zealand.
Campbell Island teal Anas nesiotis
The Campbell Island teal is one of the rarest waterfowl in the world, listed as critically
endangered on the IUCN 2005 Red List of Threatened Species, and nationally critical on the New
Zealand Threatened Species classification. It provides another classic brink of extinction
survival story as spectacular as that of the Chatham Island black robin, kakapo and takahe.
After Campbell Island teal were thought to be extinct, a small surviving population was
discovered in 1975 on Dent Island, a 23 hectare subantarctic islet with a large portion
limited to rock cover, 1.6km off Campbell Island which is 700km southeast of the South Island.
New Zealand's flightless ducks are two of the few remaining in the world. Others include
two species of flightless steamer duck, Tachyeres pteneres from Tierra del Fuego,
Chile at the bottom of South America, and T. brachypterus which is in the Falkland
Islands.
At latitude 52.5deg South, Campbell Island runs a close second to Tierra del Fuego
(latitude 54.9deg South) as the world's most southern duck location.
An accurate count was not made in 1975, but it is thought that the total population
amounted to no more than 20. Campbell Island teal had totally disappeared from all of the
other islands in the group, mainly due to predation of rats that got ashore from sealing
and whaling ships in the 19th century.
The first ducklings were reared in captivity at the Pukaha Mt Bruce National
Wildlife Centre in 1994. By 2000, the captive population of Campbell Island teal reached 60.
The Department of Conservation initially chose to establish a second population on Codfish
Island, a predator-free island off Stewart Island, as a precaution. Two releases of a total
of 24 captive bred birds had an 88 percent rate of survival.
Fifty hand-reared teal from the Pukaha Mount Bruce were released directly
onto Campbell Island in October 2004. Tracking in early 2005 confirmed 35 of the 50 birds
to be alive. In April 2005 there were 51 teal at Pukaka Mount Bruce after 20
ducklings hatched during the breeding season. Translocation of another 50 birds to
Campbell Island will take place in late 2005.
With the removal of cats and rats from Campbell Island, the Department of Conservation
expects teal to occupy their former whole range on the island within five years.
Return to flightless birds
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