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Threats
Introduced competitors and predators
Takahe
Porphyrio (=Notornis) mantelli
STATUS:
ESA -- ENDANGERED
SIZE:
Height:
24.8 inches
(63 cm)
HABITAT:
Tussock grassland
and woodlands
CONSERVATION:
Captive breeding and release; wildlife refuges; control of exotic predators
Red deer were among
a number of species introduced to British colonies like New Zealand in the 19th century by "acclimatization societies." These groups would bring in species of animals from England or elsewhere in Europe to help people living in far-flung colonial outposts feel more at home.
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Takahe
The takahe is a member of the rail family. As a group, rails were very successful at colonizing Pacific islands. They found habitats that were
virtually free of predators or competitors. As they evolved over the centuries, many of them became flightless -- and vulnerable. Then, when people colonized Pacific islands, the rails were sent reeling. With the possible exception of certain groups of freshwater fish, rails have probably suffered more extinctions than any other vertebrate family in recent times.
The takahe is the world's largest rail -- about the size of a turkey. Its feathers are brilliantly colored -- iridescent blues and coppery greens -- and it has a powerful red beak. It was probably always relatively rare, and for the first half of this century it was considered extinct. A small colony was discovered in the Murchison Mountains of New Zealand's South Island in 1948. Some takahes have been placed on predator-free Maud Island to create a reserve population. A 1992 estimate put the takahe population at about 200.
Takahes feed on fern roots and young shoots of native tussock grass -- a rather specialized diet. They get stiff competition from red deer that were imported from Europe in the 19th century. The deer eat the tussock grass, too, which is why the takahe has retreated to a small tract in the mountains. Weasels, brought to New Zealand to control rats and other introduced nuisances, are particularly adept at finding takahe nests and eating the eggs. Efforts to exterminate deer and weasels have not succeeded.
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Kakapo
Strigops habroptilus
STATUS:
ESA -- ENDANGERED
SIZE:
Length:
25Ð27 inches
(63Ð68 cm)
Weight:
Males weigh up to 7.8 pounds (3.5 kg), the female is smaller
HABITAT:
Southern beech forest
and sub-alpine grasslands
CONSERVATION:
Wildlife refuge
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Kakapo
The kakapo is the world's largest and heaviest species of parrot. It's a nocturnal, nearly flightless bird that feeds on fruits, seeds, and other plant matter. Despite strenuous efforts by the New Zealand Department of conservation, it is almost extinct -- about 50 kakapos remain alive on two small islands. Many of the plants that the kakapo feeds on only bear fruit every few years. Between these seasons, the slow-moving, solitary bird subsists on a diet of leaves and berries that it crushes -- almost chews -- with its beak. When there were no predators and no significant competitors in New Zealand, these behaviors worked well for the kakapo. But then came the Polynesians, who hunted the kakapo. With the Europeans came competitors -- introduced possums and deer that ate the kakapo's plants -- and more predators -- cats and rats that ate the kakapo's eggs and young. By the 1970s, they were virtually extinct. A tiny breeding population was discovered in 1977 on Stewart Island, a small island off the coast of New Zealand. These birds were moved to the less populated nearby islands of Little Barrier and Codfish to ensure their survival -- but the kakapo remains severely endangered, and probably won't survive much longer.
Lesser Moa
The largest birds to walk the Earth within the past few million years evolved on islands. Most of these giants are now extinct. Eleven species of moas once populated New Zealand, including Euryapteryx gravis seen in the diorama. They included the tallest birds ever known, and ranged in weight from about 40 to more than 600 pounds (18Ð272 kg). Their size afforded them protection -- very few native animals could have preyed on moas. One that could have was Haast's eagle, a gigantic raptor with a wing span of more than seven and a half feet (2.3 m). But even such a formidable predator could only have attacked moa chicks and very young birds. Like the moa, Haast's eagle is now extinct. The arrival of people, at least 1,000 years ago, was probably the major factor in the demise of moas, but many scientists believe other natural environmental changes also contributed. By about 1600, moas had disappeared completely.
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