Birds: Kiwi

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 Australian cassowaries and emus.

Are you sure it's a bird?

Regardless of what they are related to, these odd-looking birds resemble large, hairy pears! Their wings are only about 1 inch (3 centimeters) long and are useless, completely hidden under their feathers. They have no tails but do have very strong, muscular legs, which make up about a third of their total body weight, that are used for running and fighting. A kiwi has four toes on each foot (other ratites have only two or three) and its feet are quite thick, which lets the flightless bird pad silently through the forest in search of food. Despite its small size and awkward appearance, the kiwi can outrun a human and is smart and wary.

Honorary mammal?!

Looking quite different from any other bird, the kiwi has many body parts that make it seem more like a mammal. While most birds have thin skin and hollow bones to make them lighter for flying, the kiwi's skin is thick and tough and its bones are heavy and filled with marrow. Its wings have a cat-like claw on the tip, like some bats. The kiwi digs burrows instead of building nests. Its feathers are long, loose, and hair-like, and it has modified feathers that serve as whiskers on its face and around the base of its beak. It also has a relatively low body temperature (100 degrees Fahrenheit or 38 degrees Celsius) that is much more like a mammal than a bird.

Sense-sational!

The kiwi is the only bird in the world that has nostrils at the tip of its bill. It also has a highly developed sense of smell. Using only scent to find food and sensory pads at the tip of the bill to catch its food, the kiwi lives on grubs, worms, bugs, berries, and seeds. At night, these birds can be heard snuffling around in their territory; if alarmed, they will run off, then stick their bills into the air, sniffing to see if it's safe to return. Their ears are large, giving the bird a very good sense of hearing. They have been seen tipping their heads toward a sound to listen more clearly, much like humans do. It has long been thought that the kiwi is nocturnal, since it is rarely seen during the day. But researchers studying the bird on New Zealand's Stewart Island have seen them out and about during the day.

Pairing up

An adult male and female kiwi typically pair for life, but a female may choose a new male if someone more desirable wanders by. A male kiwi doesn't have beautiful songs or fancy feathers to attract a female. Instead, he will follow a female around constantly while grunting. If she's not interested, she might wander off or try to scare him away.

Breeding season is late winter to early summer. Nests might be in hollow logs or in burrows dug by the male. Clutches usually contain just one egg, but sometimes a second is laid. Kiwi eggs are smooth and beige or pale green in color. They are also huge in comparison with the female kiwi: one egg might reach up to 20 percent of its mother's weight (that would be like a 120-pound human female giving birth to a 24-pound baby)! After the egg is laid, the male takes over parenting duties. He incubates the egg and maintains the nest for nearly 80 days, but if the female returns to lay another egg, the male has to sit on the clutch that much longer.

Mini-me

A kiwi chick hatches wearing shaggy adult feathers and looking like a miniature version of its parents. No ugly baby phase for these birds! The youngster is not fed by the adults but gets its nourishment from a large reserve of yolk in its abdomen. The chick stays in the nest for its first few days, gaining strength. The young kiwi then leaves the burrow and, accompanied by Dad, begins the search for food. It will stay with the male up to 20 days and stick around in the adults' territory for months or even years.

What the future holds

Kiwis existed for millions of years with no natural predators and no threats of any kind. 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. Cars, traps set for pests, and habitat loss have also had a steady impact on the number of kiwis still in the wild.

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. Only with long-term care will the national symbol of New Zealand survive.