Air Date: Week of March 1, 2002
The kiwi bird is the national symbol of New Zealand. But the population of this unusual animal is on the wane due to a non-native, weasel-like predator called the stoat. As Allan Coukell reports, a kiwi recovery program named Operation Nest Egg has succeeded in increasing the number of kiwis by isolating the babies until they are old enough to fend for themselves.
CURWOOD: Just as Americans look to the bald eagle, the people of New Zealand turn to the kiwi as their national symbol. Kiwis are large and flightless. And they evolved in the absence of predatory mammals. But, 200 years ago, Europeans came to New Zealand. And the cats, dogs and other mammals they brought set the kiwi on the path to extinction.
Allan Coukell has our story about an effort to save one of the most endangered populations of kiwi.
[SOUND OF BOAT STARTING]
MAN: Come up through here and go across that way I'm going to have you right behind.
COUKELL: In the harbor at Picton, New Zealand, two young birds in a plywood box are loaded aboard a boat. They started their journey 500 miles south of here, in a dense and tangled rainforest. Now they'll spend an hour crossing from the mainland to a small, offshore island. This is Operation Nest Egg, an ambitious attempt to save the kiwi.
[SOUND OF BOAT AND KIWI]
COUKELL: One hundred years ago, about five million kiwi could be heard at night in New Zealand's forests. Now, the kiwi population is less than two percent of its historical size and numbers are halving every decade.
COUKELL: The kiwi is an ancient bird. Found only in New Zealand, it diverged from its other flightless relative, the African Ostrich, and the Australian Emu, more than 80 million years ago. Hugh Robertson is the coordinator of research with the New Zealand Department of Conservation Kiwi Recovery Program. He says, with it's shaggy, hair-like feathers, long, slim beak and whiskers, and the keen sense of smell it uses for finding insects and worms, the kiwi is well-adapted for life on the forest floor.
ROBERTSON: They have all sorts of unusual features such as nostrils at the tip of the bill, rather than at the base of the bill. They have no tail, which is unique amongst birds. Their wings are really short little stumps, only an inch long. They run around at night on the forest floor hunting out invertebrates. And, yeah, they're quite an interesting creature.
COUKELL: Adult kiwi are tough and fast, and have sharp claws. It's the juvenile birds that are more vulnerable to predators. The most endangered population of kiwi is found in Okarito Forest on the West Coast of New Zealand's South Island. And their main enemy is a weasel-like carnivore, the stout.
Chris Rickard is the manager of the Okarito Brown Kiwi Recovery Program. In 1996, he surveyed the entire 25,000 acres of Okarito Forest, finding fewer than 200 kiwi. Even worse, Rickard says, was discovering the mortality rate among young kiwi.
RICKARD: We've monitored 26 chicks and we've lost 24 of those. We know that the survival rate is very, very low. It's estimated at 96 percent mortality.
COUKELL: So Rickard and his colleagues at the Department of Conservation devised a plan to keep the baby kiwis away from predators until they're big enough to fend for themselves.
RICKARD: We have 30 pairs that we monitor throughout the forest. And during the birding season they get checked once a fortnight to determine whether they're breeding. And all the chicks and eggs from those piers are taken into captivity. We didn't have the funding and the ability to trial the large-scale stoat control, so we went with something to buy us time.
COUKELL: The captivity program, better known as Operation Nest Egg, works like this. The adult kiwi are left undisturbed in the forest while they incubate their eggs. This takes a surprisingly long time, about 75 days. But just before the eggs hatch, or very soon after, the young kiwi are removed from the forest. After only a few days in captivity the hatchlings are able to forage for food on their own and they're relocated to an island sanctuary.
[SOUND OF BOAT AND WATER]
COUKELL: The boat from Picton pulls up at Motuara Island. Conservation workers unload their gear onto the pier and a few minutes later carry the wooden box of kiwis up a steep trail into the bush.
[SOUND OF HIKING THROUGH FOREST]
COUKELL: A mile long and a few hundred yards wide, Motuara Island is a slip of land covered in a scrubby forest. Ron van Merlo is the Department of Conservation field worker who will release the kiwi chicks today. He says the island is ideal because it's far enough from the mainland to keep it free of stoats.
VAN MERLO: This is quite a good spot for them to just have a gentle introduction to the wilderness, get to learn a few things away from predators, learn how to fend for themselves, feed themselves, look for places to shelter, do normal kiwi things in a easier sort of environment.
COUKELL: Van Merlo sits on the forest floor, holding the birds on his lap.
VAN MERLO: You just want to hold them.
[SOUND OF BIRDS]
COUKELL: His large, strong hands move gently and methodically, checking each chick a final time before releasing it on the island.
VAN MERLO: They've got very strong legs. The rest of them is a little bit fragile, so we just handle them by the legs so that they don't get squashed.
[KIWI CHICKS CHIRPING]
COUKELL: These are the last of 24 kiwi chicks released on Motuwara Island this year. All of them wear radio tracking devices. And every few weeks for an entire year, Ron Van Merlo or another field worker will find each bird and check its growth and physical condition.
[SOUND OF RADIO DEVICES]
VAN MERLO: So this is TX -45. So now I'm just going to tape its legs up to weigh it. It looks a bit drastic, but hang them upside-down from the hook of the scales-- So long as the bird's not obviously really stressing out about it all, hanging them up briefly upside-down doesn't do them no harm. That's 1.05, which is good.
COUKELL: By the end of the year the birds will quadruple in size, up to almost four pounds. They'll then be big, fast, and smart enough to defend themselves against stoats and they'll be moved back to Okarito Forest on the mainland. With each individual chick taken from the forest, moved hundreds of miles, handled dozens of times and eventually transferred home again, this is an extremely labor-intensive process. It's also about to end.
Four years of Operation Nest Egg have bolstered Okarito kiwi numbers by almost a third, giving conservation staff the time and confidence to develop a large-scale pest control operation right in Okarito Forest. They hope this will insure that the timeless call of the kiwi continues into the future.
For Living on Earth I'm Alan Coukell on Motuwara Island, New Zealand.
[CALL OF KIWI]
[MUSIC: David Hudson, "Talkative Didgeridoo"]
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