New Zealand a Noah's Ark for Conserving Bizarre Birds
for National Geographic News
|September 21, 2004|
When New Zealand split away from the supercontinent Gondwana some 80
million years ago, its flora and fauna were left to develop in
The result was a virtual Noah's Ark of bizarre animals: Flightless, nocturnal parrots that hike several kilometers at a time; yellow-eyed penguins that nest in forests; and bad-tempered kiwis with skin as tough as shoe leather, poor eyesight, and a highly developed sense of smell.
Living in a paradise without predators, these odd species thrived. But when the first human settlers, the Maoris, arrived about a thousand years ago, the rats and dogs they brought with them wreaked havoc on the islands' wildlife. Europeans arrived in the early 1800s, bringing with them mustelids (stoats, ferrets, and weasels), cats, and two more species of rats. In addition to the threats posed by newly introduced predators, imported goats, sheep, and cattle competed with the native animals for food.
New Zealand's native bird populations plummeted.
"Land clearance has removed the majority of habitat available," said Doug Armstrong, senior lecturer in wildlife ecology at Massey University in Auckland. "But there would still be habitat to support good populations of all bird species, I think, if it wasn't for introduced predators."
Conservationists working to protect and restore these populations determined that the only way to save New Zealand's threatened bird species was to move them to predator-free offshore islands. Don Merton is a senior technical officer at New Zealand's Department of Conservation. Ha said there have been 198 translocation projects involving 34 bird species to 75 offshore islands since the 1890s.
Creating Predator-Free Environments
Turning an island into a sanctuary is harder than it sounds. One can't just drop off a dozen hihi birds, wish them luck, and hope that they survive.
"The key is to develop a working theory on what caused the original extirpation, [and determine] whether those factors are still operating, and what management is required to have a viable population," Armstrong, the Massey University wildlife ecologist, said.
Before embarking on a translocation project, scientists must first learn everything possible about a target species, from mapping out their historical home range to identifying nesting preferences. Once a species' needs are known, clearing an island of introduced predators and restoring its natural habitat can be a mammoth task. If the population comes from captive stock, the birds must be taught how to survive in the wild.
If the birds are captured in the wild, scientists must ensure that populations are genetically compatible with existing populations and that the original population is not being depleted.
Once the animals are safely established, they must be monitored. Scientists keep careful statistics on the abundance, survival, and reproduction of a population to determine whether they can sustain themselves.
In New Zealand, there are issues beyond the typical scientific concerns to address. The Tangata Whenuathe Maori tribes with traditional connections to the areamust be consulted. And since the animals are so unusual, so too are the challenges.
"The kakapo are particularly vulnerable to predators, because they are flightless, smelly, and attempt to a avoid predators by sitting still," Graeme Elliot, a scientist on the National Kakapo Team at the New Zealand Department of Conservation, said. "Worse yet, they breed only when the rimu tree goes into fruitan event that occurs, on average, every 23 to 25 years."
In addition, female kakapos don't start breeding until they are 9 to 11 years old. (See Sidebar)
Sometimes, even if conditions seem exactly right, the project still ends in heartbreak.
After exhaustive planning and preparation, the hihi bird was reintroduced to Mokaia Island in 1994. Despite intensive management and supplemental feeding, the population languished. Many birds died, and eventually the surviving ones were translocated elsewhere. A fungal disease that was particularly virulent on Mokaia Island was eventually identified as a major source of mortality.
Saving Species, One Population at a Time
Thankfully, New Zealand's efforts to save its endangered bird species are largely qualified success stories.
In 1980, due to habitat destruction and predation, only five black robins remained in the entire world. Worse yet, only one was a breeding female. Today the black robin population exceeds 250 birds. The takahe, once thought extinct, now has a population of 120 birds.
The saddleback, a black wattlebird with a tan saddle of feathers on its back and a pendulous orange wattle at the base of its bill, has been translocated 27 times since 1925 and now inhabits approximately 16 islands. The birdonce on the very edge of extinctionis now on the lowest, safest rung of the international Red List of endangered species, and is considered a stabilized population.
The flightless, smelly kakapo, once all but extinct, has been nurtured and rebounded to become a thriving population of 83. Each bird has been named: Richard Henry is the grand old male who likes to be tickled under the chin. Sinbad is a fastidious bird with unusually tidy eating habits. Felix is named after a brand of cat food, which is what it would have been if it had been left on Stewart Island. Zephyr, the most productive female, seems to have a thing for Felix, who is the father of five of the female's chicks.
As successes mount, New Zealand's conservationists are starting to reintroduce their charges to New Zealand's mainland. The obstacles are substantial.
"Dispersal is the main one," said Colin Miskelly, a technical support manager at the New Zealand Department of Conservation. "Also restrictions on predator control methods due to multiple land uses and legislative constraints."
In several areas, high-tech fences have been erected and special dogs and ferrets have been used to clear predators out.
In the next few weeks, saddlebacks will be released in Boundary Stream Scenic Reserve on the eastern edge of the Maungaharuru range on the North Island of the New Zealand mainland.
"This will be the first attempt for some time to bring a Red-Listed species back to an unfenced mainland area," Armstrong said.
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