Science / Medicine : An Avian Enigma : New Zealand’s Kiwi Proves Astonishing, but Its Future Is Grim

Obscured by a hide that he had constructed from the fronds of giant tree ferns, John McLennan had squatted for five hours under the stars of the Southern Cross, watching a 3-foot-deep hole.

With light-gathering, infrared binoculars raised, the New Zealand scientist waited for the emergence of a bird so strange that when it was first described in 1813, English naturalists dismissed the report as a hoax: With barely visible stumps for wings, no external tail and a bill bordered with bristles at the face and nostrils at the tip, the burrowing, cone-shaped kiwi is an avian enigma wrapped in shaggy, hair-like feathers.

Because it is stealthy and active only at night, the habits of New Zealand’s national bird have remained largely unknown since the time of its discovery. Today, however, McLennan’s studies of this 2-foot-long, flightless bird reveal that the kiwi’s behavior is even more astonishing than its appearance. The silly-looking kiwi of shoe polish fame is actually a sort of super-bird whose behaviors may harken back to a lofty ancestry: its closest relative is now thought to be an extinct monster that stood 11 feet tall.

Death of a Symbol

But the most alarming finding of his six-year study is that New Zealand is fast eradicating its national emblem. The New Zealand press has taken to calling it “kiwicide.”

Kiwis were once so numerous that Maoris, Polynesians who invaded the island 1,000 years ago, made full-length cloaks from their feathers. Early European explorers feasted on their gamy flesh. But today, the smallest of the three kiwi species, the little spotted kiwi, now survives only on a single island sanctuary, Kapiti Island off the mainland. Populations of brown kiwi, the national bird, may have declined by 90% this century. The greater spotted kiwi, the largest species, are few but the exact numbers are unknown.

McLennan waited at the hole for a male kiwi to leave its burrow for its nightly hunt. With its long, nostril-tipped bill, the kiwi finds its prey by smell, stabbing the earth to seize invertebrates such as the 9-inch New Zealand bushworm. McLennan wanted to examine the burrow: He wondered if the 5-inch egg the male was incubating had hatched.

Then, shortly after 1 a.m., the red-bearded ecologist heard the crashing of an approaching animal. The female kiwi was coming.

McLennan waited in silence for many minutes, wondering what the female would do next. And then, he recalled, “I felt this little tap on my foot. Her nose was right on my boot.”

Fearless Males

McLennan was lucky it was a female. He has found that males, during the breeding season, will fearlessly attack intruders, including humans, slicing at invaders with razor-sharp, toxin-tipped toenails. “I’ve been walking alone, and they dash out like a hit-and-run driver--they’ll hit you hard on the leg, striking out with the feet, and dash away,” McLennan said.

Although kiwis seem dull-witted, nearly blind and defenseless in captivity, the wild kiwi is nothing of the sort. McLennan has discovered that the kiwi’s eyesight is excellent; although flightless, the kiwi can cross rushing streams and scale huge boulders. Further, McLennan found that female brown kiwis are capable of staggering feats of reproduction. Laying the largest egg for its body weight of any bird that ever lived, a 4-pound brown kiwi can, if its nest fails or is destroyed, produce as many as five, 1-pound eggs in a single breeding season--the equivalent of an average-sized woman bearing five, 30-pound babies.

The giant eggs reveal the kiwi’s likely lineage. The kiwi’s closest relative is probably the moa, some species of which stood 11 feet tall. Its egg could make an omelet for 12. DNA studies also suggest the link. Today’s studies of kiwis may yield the best guesses yet advanced about how this enormous bird, extinguished after Polynesian man arrived on the New Zealand islands 1,000 years ago, may have lived, McLennan said.

New Zealand is the only place in the world where the kiwi is found. And it would seem a safe haven: The usual culprits in recent extinctions--pollution, poaching and illegal trade in endangered species--aren’t big problems in this pristine and peaceful nation, where sheep farming is the primary industry. Yet according to the International Union for the Conservation of Nature and Natural Resources, New Zealand faces one of the most rapid rates of extinction in the world.

Part of the problem is development, as forests are cleared for farms and homes. Another part are the pets and pests Europeans brought here 300 years ago: stoats, dogs, cats, ferrets, pigs, rats, Australian possums, Japanese deer, a United Nations of species. Many of them have overrun the country. And even though New Zealanders are now trying to get rid of some of the invaders, kiwis, as well as other species, are caught in the cross-fire.

“I could lead you to the deathbeds of thousands of kiwis,” said Mike Rudge, who like McLennan works for the New Zealand Department of Scientific and Industrial Research.

“It is absolutely amazing,” he said, “that this is our national bird, and kiwis are under literally under siege.”

One of those deathbeds would be Waitangi forest, formerly one of the brown kiwi’s major strongholds. More than a thousand kiwis lived there in August, 1987. By the end of that September, the population had been halved.

The culprit was found on the last day of that month: it was a single German shepherd bitch that had run wild.

Kiwis evolved in the absence of mammalian predators, which is why there was never any reason to fly. Though they will fearlessly defend breeding territory, adults will leave their young (usually under the daytime care of the male) for long hours while they go on their nighttime hunts. By its fifth or sixth night of life, the chick emerges from the burrow and tries to feed itself. “They’re really nice to watch then, shuffling around the burrows,” McLennan said.

When it first emerges, the chick “is a perfect adult kiwi in miniature, a little powder puff of feathers on the forest floor,” McLennan said. “They’re really terribly vulnerable to stoats, cats and ferrets then.”

Kiwi Census

McLennan counted only three pairs of brown kiwi, and two unmated adults, in his 700-hectare study area. They laid 21 eggs in two years. Fifteen eggs failed or were destroyed by predators. Six hatched. Three chicks were killed before fledging.

Only three chicks fledged in two years--a per-year gain of half a chick per pair. And what happens once the chick leaves the nest a month later? “We don’t know,” answered McLennan.

The picture looks so bad for kiwis that some hopeful organizations have launched kiwi rescue schemes. The idea is to find and capture kiwis in areas slated for development and move them to new areas. But the kiwi’s nocturnal stealth usually thwarts such efforts.

In August, 1981, Royal Forest and Bird Society branch Chairman Peter Winter was invited to participate in one such rescue attempt five days before 50 acres of North Island forest--prime kiwi habitat--were to be burned and crushed to make way for a new farm block in North Taranaki.

Winter related: “We made five visits in all. The number of kiwi-catchers (all volunteers) ranged from 10 on one night to four. We mimicked kiwi calls and learned to distinguish the real from the false, but we did not catch kiwi. In fact, nobody even saw one.” Although the volunteers estimated that about 12 kiwi pairs lived in the area, none could be rescued before the burn-off.

The North Taranaki was a relatively small tract. Last year, New Zealand’s Lands and Survey Department cleared 3,200 hectares of North Island scrubland to create 12 farms under a land settlement scheme. “When that development went in,” ecologist Rudge said, “you probably annihilated the last large bastion of kiwi in Northland.”

Endangered by Trappers

In captivity, kiwis are known to live for more than 20 years. But among the threats they face in the wild is one that left a lasting mark on three of the eight birds McLennan studied in Northland: Missing toes indicated that these adults were caught in leg-hold traps, set by fur-trappers to catch introduced Australian possums. From reports he had heard from area residents, a dozen kiwis in the study area were killed in these traps in the previous 12 years.

The New Zealand government encourages possum trappers. After all, the Australian possums destroy acres of trees, pilfer from farmers, and usurp habitat and food from native animals. The foreign animals, brought here to start a fur trade, now so overrun some forested areas that entire hillsides are collapsing from erosion. But in the effort to preserve New Zealand’s forests and scrub, trappers may be unwittingly eradicating the bird that symbolizes the country’s uniqueness.

The irony does not escape McLennan. “In this country, people can take over prime forest, knowing they are going to wreck kiwi habitat, destroy kiwi nests, and place traps that may well disable kiwis. But if they shot a kiwi and were caught, they’d be fined. It just doesn’t make sense.”