Range:

New Zealand

Habitat:

Mostly forest, also found in scrub and grassland

Is it a fruit?

The word "kiwi" often brings to mind the image of something small, brown, fuzzy, and found in the produce section of your local supermarket. But the kiwi is not a fruit—that's kiwifruit, which is native to eastern Asia! About the size of a chicken, the kiwi is a small, flightless, and nearly wingless bird found only in New Zealand.

Like its larger cousins the cassowary, emu, ostrich, and rhea, the kiwi is classified as a ratite. Most birds have a special ridge on their sternum, called a keel, where flight muscles attach, but ratites don't need keels because they don't fly. Scientists thought for many years that the kiwi's closest relative was another ratite called a moa, an extinct bird that was also native to New Zealand. However, recent genetic studies have shown that Africa's ostrich is related to the moa while the kiwi is more closely related to Australia’s cassowary and emu.

Are you sure it's a bird?

Regardless of what it’s related to, this odd-looking bird resembles a large, hairy pear! Its wings are only about 1 inch (3 centimeters) long and are useless, completely hidden under the feathers. The kiwi has no tail but does have very strong, muscular legs, which make up about a third of the bird’s total body weight, that are used for running and fighting. Four toes (other ratites have only two or three) on each thick foot allow the flightless bird to pad silently through the forest in search of food. Despite its small size and awkward appearance, the kiwi can outrun a human and is quite wary.

About the same size as a chicken, a kiwi's eggs are almost as big as those of the emu and are one of the largest in proportion to body size of any bird in the world.
The kiwi is the national symbol for New Zealand.
The kiwi is thought to be the world's most ancient bird, evolving over 30 million years ago.
A female kiwi can lay 100 eggs in her lifetime.
The kiwi has the lowest body temperature of any bird.

Our first kiwi
The San Diego Zoo’s first kiwi arrived from the Auckland Zoo in New Zealand in December 1954, the only kiwi at that time to live in the Western Hemisphere. That zoo’s director had visited our zoo and determined, after looking it over carefully, that a kiwi would do well here. The bird was named Belle, after our director at that time, Belle Benchley. Ornithologists and scientists came from around the U.S. just to view our kiwi. The San Diego Chapter of The Kiwis (formerly American Airlines flight attendants) donated funds for the construction of a kiwi enclosure.

The bird came with this greeting from the Auckland Zoo: “The kiwi we are sending you is an adult. The biographical details are that this bird was sent to us three and a half years ago from Opotiki, a town not far from Rotorua in a district where there is still quite a lot of native bush. It is a typical North Island kiwi Apteryx australis mantelli. We have no great ideas as to longevity of kiwis. I hope you have a very successful time with the bird and commiserate with you in advance over the difficulties you will have trying to marry in the desire for everyone to see the kiwi and your desire to keep it healthy and getting enough sleep.”

This concern was well-founded. With its nocturnal habits, the kiwi preferred to sleep in a secluded spot in its well-shaded enclosure during the day and forage for food at night. Mrs. Benchley noted in the Zoo’s member magazine, ZOONOOZ, in 1955, “… the kiwi is here, located in an excellent cage, and since this cage was designed to give the bird a maximum of security and a minimum of excitement or fear for its own security, I know that you, the Zoo visitor, will have to be satisfied with fleeting glances, or partial success in seeing your first kiwi, just as you might in the wild…”

More kiwis arrive
A few years later, Belle the kiwi turned out to be a male and was renamed Benjamin. He was introduced to his potential mate, Nancy, in 1967, a gift from the Wellington Zoo, the Wellington City Council, and the Government Wildlife Division of New Zealand. Nancy arrived via a well-advertised Kiwi Flight on Air New Zealand. Both Benjamin and Nancy died in 1968.

In 1969, a nocturnal exhibit was built for a new pair of kiwis, given to the City of San Diego on its 200th anniversary by New Zealand Wildlife Service. The home for Toa and Uha, whose names are Maori for “male” and “female,” had a unique feature at the time: it was dimly lit by a blue light during the day so Zoo guests could see them most active, and brightly lit at night, to encourage the birds to sleep. Toa died in 1972, but a new mate for Uha, named Toa II, arrived on loan from the National Zoo in Washington, D.C. in 1973. Yet, like Belle/Benjamin, Uha had difficulty living up to “her” name, and the discovery that both birds were male did little for our hoped-for kiwi breeding program.

Kiwi chicks
It was not until 1979 that a breeding program was started here in earnest, with kiwis from the San Diego Zoo, the National Zoo, which had hatched a kiwi in 1975, and the Auckland Zoo. However, utilizing both indoor and outdoor exhibits and rotating the five kiwis in the breeding program still produced nothing but 16 infertile eggs in 4 years. In 1983, the right combination was found at last, and our first kiwi hatched. Sadly, the chick died from a bacterial infection three weeks later. A second chick hatched in 1986.

Since then, we’ve had much better success with kiwi hatchings. Currently, there are four brown kiwis at the Zoo, but they live in off-exhibit areas, as the old nocturnal kiwi house is being replaced as part of our new Australian Outback habitat, scheduled to open in spring 2013.

Kiwi recovery
The kiwi existed for millions of years with only one natural predator—the now-extinct laughing owl—and no threats of any kind. When the Maori people established themselves in New Zealand in the 1300s, they used kiwi feathers to adorn cloaks worn by their chiefs and used the birds as food, hunting them at night by imitating kiwi calls. But in the late 1800s, settlers moved into kiwi territory, bringing dogs, cats, ferrets, stoats, and rats that ate kiwi eggs or the birds themselves. The settlers prized kiwi feathers, too—for trout flies! Kiwi leg bones were popular as well for making pipe stems.

New Zealand passed a law in 1908 prohibiting the hunting, capture, or killing of kiwis, but the $100 penalty did little to control the situation, and in 1921 the kiwi was declared an “absolutely protected bird.” Its popularity grew, and the kiwi was adopted as New Zealand’s national emblem. Coins, postage stamps, fighting troops, and shoe polish all carry the name or image of the unique bird. New Zealanders even accepted the nickname “kiwis” given them by their allies during World War II.

Operation Nest Egg
Today, 80 percent of kiwi habitat has been destroyed, and the birds continue to fall prey to dogs, weasels, cats, ferrets, pigs, people, cattle guards, cars, swimming pools, and possum traps. Still, the birds are highly adaptive and have been seen in New Zealand cow pastures and plantations. Every year, 95 percent of all kiwi chicks are killed before they reach the age of 6 months, and every 2 years the kiwi population decreases by about 10 percent.

A few years ago, New Zealand began a kiwi recovery program. People living near kiwi areas have learned to keep their dogs leashed and to slow their cars when they see a kiwi caution sign by the road. Operation Nest Egg collects eggs from the wild and raises the chicks until they are large enough to defend themselves against predators following release into the wild.

Kiwi conservation
In 2009, San Diego Zoo Global formed collaborations with local ranchers on a private island off the coast of western New Zealand, Massey University, in-country scientists, and the native Maori people to delve into the ecology of the brown kiwi, which has been in decline for decades. Learning about the reproductive ecology of this bird is the only way to ensure that its populations will survive and thrive. The island is secluded, protected habitat with a high density of kiwis.

Techniques were developed in our labs to identify individual kiwis by their DNA and, and ultrasound procedures were used to monitor growth of ovarian follicles to estimate egg-laying time. This newfound knowledge was then successfully applied to birds on the island. Eggs laid by zoo kiwis tend to be much smaller and have a much lower fertility rate than their wild counterparts. By monitoring egg development in the wild, we hope to discover ways to improve fertility and survival of eggs at our facilities.

Important data can also be gleaned from radio-tracking devices on the birds. After months of fieldwork, 47 adult kiwis on the island now have a radio transmitter attached to a leg, and 41 kiwi nests were documented, allowing us to explore the importance of habitat and behavior on the nesting success of this rare and reclusive species.

The birds are identified with transponder tags, such as those used to microchip domestic pets. The radio transmitters reveal a great deal about where the birds go and how far they travel for food. One area of study is mate choice and how long kiwis stay together. Ongoing research will compare hormone levels in wild birds to those in managed care and also observe chick dispersal patterns for this long-lived bird.

A few fascinating facts have emerged from our efforts so far, such as finding three males incubating a single egg! Read a blog post from one of our kiwi researchers in the field...