Kiwi (bird)

Kiwi are special flightless birds that live only in New Zealand. They belong to a group called Apterygiformes and are about the size of a domestic chicken. Kiwis are part of a larger family of birds known as ratites, which includes ostriches, emus, rheas, and cassowaries.

There are five kinds of kiwi, and most of them are rare and need protection. Their homes have been harmed by cutting down trees, but they are safe in big forest areas and parks. The biggest danger to kiwis now comes from animals that are not from New Zealand and try to hurt them.

Kiwis have some very interesting features. Their wings are so small that you can’t see them under their special feathers. They lay huge eggs—up to 20% of their body weight! Kiwis also have strong legs and use their long beaks to find food before they even see it. Because of these cool traits, kiwis are famous all over the world.

The kiwi bird is a symbol of New Zealand, and people from that country are often called "Kiwi" too.

Etymology

The word kiwi comes from the Māori language and sounds like the bird's call. When the first people from Polynesia arrived in New Zealand, they may have used the name kiwi because it reminded them of another bird called the bristle-thighed curlew.

The name is usually written with a small "k" and does not change when we make it plural in English. This is different from when we talk about people from New Zealand, who are called "kiwis."

Taxonomy and systemistics

The name Apteryx comes from Ancient Greek words meaning "without wing." Scientists used to think kiwis were closely related to another bird from New Zealand called the moa. But newer studies using DNA show that kiwis are actually more closely related to birds called elephant birds from Madagascar, and also to emus and cassowaries, than to moas.

In 2013, researchers discovered an older type of kiwi called Proapteryx from Miocene deposits. This older kiwi was smaller and could probably fly, which helps explain how kiwis got to New Zealand separately from moas.

Species

There are five living species of kiwi today, along with some subspecies. There was also one species of kiwi that has gone extinct.

Relationships in the genus Apteryx

Image	Scientific name	Common name	Distribution	Description	Population	IUCN Status	Population Trend
	Apteryx maxima or Apteryx haastii	Great spotted kiwi or roroa	New Zealand	The largest species, standing about 45 cm (18 in) tall, with females weighing about 3.3 kg (7.3 lb) and males about 2.4 kg (5.3 lb). It has grey-brown plumage with lighter bands. The female lays one egg a year, which both parents incubate. The population is estimated at over 20,000, distributed through the more mountainous parts of northwest Nelson, the northern West Coast, and the Southern Alps of the South Island.	9,300	VU
	Apteryx owenii	Little spotted kiwi	Kapiti Island	A small kiwi the size of a bantam, standing 25 cm (9.8 in) tall, with the female weighing 1.3 kg (2.9 lb). She lays one egg, which is incubated by the male. This small, docile kiwi is unable to withstand predation by introduced pigs, stoats and cats, leading to its extinction on the mainland. There are about 1350 on Kapiti Island and it has been introduced to other predator-free islands, where it appears to be getting established with about 50 on each island.	1,500	NT
	Apteryx rowi	Okarito kiwi, rowi or Okarito brown kiwi	South Island	The Okarito kiwi, first identified as a new species in 1994, is slightly smaller than the North Island brown kiwi, with a greyish tinge to the plumage and sometimes white facial feathers. Females lay up to three eggs in a season, each one in a different nest. Male and female both incubate. Distribution is now limited to a small area on the West Coast, but studies of ancient DNA have shown that, in prehuman times, it was far more widespread on the western side of the South Island and lived in the lower half of the North Island, where it was the only kiwi species detected.	350-400	VU
	Apteryx australis	Southern brown kiwi, tokoeka or common kiwi	South Island	Almost as big as the great spotted kiwi and similar in appearance to the brown kiwi, though its plumage is lighter in colour. It is relatively numerous. Ancient DNA studies have shown that, in prehuman times, the distribution of this species included the east coast of the South Island. Several subspecies are recognised: The Stewart Island southern brown kiwi, Apteryx australis lawryi, is from Stewart Island/Rakiura. The northern Fiordland tokoeka (Apteryx australis ?) and southern Fiordland tokoeka (Apteryx australis ?) live in Fiordland, the remote southwest part of the South Island. These subspecies of tokoeka are relatively common and are nearly 40 cm (16 in) tall. The Haast southern brown kiwi or Haast tokoeka, Apteryx australis 'Haast', is the rarest taxon of kiwi with only about 300 individuals. It was identified as a distinct form in 1993. It occurs only in a restricted area in the Haast Range of the Southern Alps at an altitude of 1,500 m (4,900 ft). This form is distinguished by a more strongly downcurved bill and more rufous plumage.	16,500	VU
	Apteryx mantelli or Apteryx australis	North Island brown kiwi	North Island	A. mantelli (or A. australis before 2000 and still in some sources) females stand about 40 cm (16 in) tall and weigh about 2.8 kg (6.2 lb), while the males weigh about 2.2 kg (4.9 lb). The plumage is streaky red-brown and spiky. The female usually lays two eggs, which are incubated by the male. The North Island brown has demonstrated a remarkable resilience: it adapts to a wide range of habitats, including non-native forests and some farmland. It is widespread in the northern two-thirds of the North Island and is the most common kiwi, with about 35,000 remaining.	10,000-19,999	VU
	Apteryx littoralis	"Kiwi of the shore"	North Island	A. littoralis is the only known extinct species of Apteryx, known from Pleistocene-age rocks that are roughly one million years old. The holotype, NMNZ S.36731, is a tarsometatarsus. The holotype was found to be most similar to the Okarito and North Island brown kiwi, although it was stouter and proportionally more narrow. It is thought to have been restricted to coastal habitats due to volcanism present on the North Island at this time.

Description

Kiwi birds are special because they can't fly. Like other flightless birds such as ostriches, emus, rheas, and cassowaries, they don't have a special bone called a keel that helps birds fly. Their wings are so tiny that you can't see them under their soft, hair-like feathers.

Kiwi birds have some other unique features too. Their bills are long and very sensitive to touch, and their eyes are small, which makes them better at using their other senses like hearing and smell to find food. Even though they don't see well, they can still live normally without their sight.

Behaviour and ecology

Before humans arrived in New Zealand, the only mammals were three types of bats. Birds, along with some reptiles, insects, and snails, filled the roles that other animals like horses, wolves, and mice usually have.

Kiwis are mostly active at night, possibly because of predators, including humans. In areas without introduced predators, kiwis can be seen during the day. They live in subtropical and temperate forests but must adapt to other areas like scrubland, grasslands, and mountains. Kiwis have a strong sense of smell, which is unusual for birds, and they are the only birds with nostrils at the end of their long beaks. They eat small insects, seeds, grubs, worms, fruit, small crayfish, eels, and amphibians. Using their sense of smell, kiwis can find food underground without seeing or feeling it. While it is believed kiwis rely on smell to find food, experiments show they may also use sound and vibrations.

Mating and breeding

Male and female kiwis often stay together for life. During the mating season from June to March, they call to each other at night and meet in a burrow every three days. These pairs can stay together for up to 20 years. Unlike most birds, kiwis have two functional ovaries. Usually, only one egg is laid each season. Kiwi eggs are very large compared to the bird's size—about six times the size of a chicken egg. Even though kiwis are about the size of a chicken, their eggs can be one-quarter the weight of the female. The male incubates the egg, except for the great spotted kiwi, where both parents help. It takes 63 to 92 days to incubate the egg. Producing such a large egg is very tiring for the female, who must eat three times more food during the thirty days it takes to develop the egg. Two to three days before laying, the female has little room for food and must fast.

Research suggests that kiwis evolved from smaller flying birds. The large eggs help kiwi chicks hatch ready to move and have extra nutrition to survive for two and a half weeks. In the past, New Zealand had no animals that ate eggs on the ground, and the mobile chicks could escape from flying predators that ate chicks.

Pests

Some tiny insects, called lice, live only on kiwi birds. These lice belong to groups named Apterygon and Aptericola. They stick to the kiwi's feathers and skin, getting food from them.

Status and conservation

Nationwide studies show that only about 5–10% of kiwi chicks survive to become adults without help. As of 2018, over 70% of kiwi populations were not being managed. However, in areas where pests are controlled, survival rates for North Island brown kiwi can be much higher.

Efforts to protect kiwi have had some success. In 2017, two species were moved from endangered to vulnerable by the IUCN. In 2018, the Department of Conservation released its current Kiwi Conservation Plan.

Sanctuaries

In 2000, the Department of Conservation set up five kiwi sanctuaries to develop methods to protect kiwi and increase their numbers.

There are three kiwi sanctuaries in the North Island:

• Whangarei Kiwi Sanctuary (for Northland brown kiwi)
• Moehau Kiwi Sanctuary on the Coromandel Peninsula (Coromandel brown kiwi)
• Tongariro Kiwi Sanctuary near Taupō (western brown kiwi)

and two in the South Island:

• Okarito Kiwi Sanctuary (Okarito kiwi)
• Haast Kiwi Sanctuary (Haast tokoeka)

A number of other mainland conservation islands and fenced sanctuaries have significant populations of kiwi, including:

• Zealandia fenced sanctuary in Wellington (little spotted kiwi)
• Sanctuary Mountain Maungatautari in Waikato (brown kiwi)
• Bushy Park Forest Reserve near Kai Iwi, Whanganui (brown kiwi)
• Otanewainuku Forest in the Bay of Plenty Region (brown kiwi)
• Hurunui Mainland Island, south branch, Hurunui River, North Canterbury (great spotted kiwi)

North Island brown kiwi were introduced to the Cape Sanctuary in Hawke's Bay between 2008 and 2011, which in turn provided captive-raised chicks that were released back into Maungataniwha Native Forest.

Sanctuaries for kiwi are also referred to as 'kōhanga sites' from the Māori word for 'nest' or 'nursery'.

Operation Nest Egg

Operation Nest Egg is a programme run by the BNZ Save the Kiwi Trust—a partnership between the Bank of New Zealand, the Department of Conservation and the Royal Forest and Bird Protection Society. Kiwi eggs and chicks are removed from the wild and hatched and/or raised in captivity until big enough to fend for themselves—usually when they weigh around 1200 grams (42 ounces). They are then returned to the wild. An Operation Nest Egg bird has a 65% chance of surviving to adulthood—compared to just 5% for wild-hatched and -raised chicks. The tool is used on all kiwi species except little spotted kiwi.

1080 poison

Main article: 1080 usage in New Zealand

In 2004, activist Phillip Anderton claimed a kiwi had been poisoned, but investigations showed he lied. He had used a kiwi that had been caught in a possum trap. Monitoring shows that kiwi are not at risk from the use of biodegradable 1080 poison.

Threats

Introduced animals, such as stoats, dogs, ferrets, and cats, are the main threats to kiwi. Stoats are the biggest threat to kiwi chicks, while dogs are the biggest threat to adult kiwi. Stoats cause about half of kiwi chick deaths in many areas. Young kiwi chicks are vulnerable to stoats until they reach about 1–1.2 kg (2.2–2.6 lb) in weight. Cats also prey on kiwi chicks. These animals can cause large and sudden drops in kiwi populations. Dogs can easily track and catch kiwi because of their strong scent. Motor vehicles are a threat to kiwi where roads pass through their habitat. Badly set possum traps can also harm kiwi.

Habitat loss is another major threat to kiwi. The small size and restricted distribution of some kiwi populations make them more vulnerable to inbreeding. Research shows that with predators and other dangers, less than 5% of kiwi chicks survive to adulthood.

Relationship to humans

The Māori people of New Zealand believed that kiwi birds were protected by Tāne Mahuta, the god of the forest. They used kiwi feathers for special cloaks called kahu kiwi. Today, kiwi feathers are collected only from birds that die naturally or in accidents. Kiwi birds are no longer hunted, and some Māori people now act as guardians for these birds.

The kiwi bird has become an important symbol for New Zealand. It first appeared on military badges in the late 1800s and later became widely known when a shoe polish called Kiwi Shoe Polish was sold around the world. During World War I, New Zealand soldiers were called "Kiwis," and a large kiwi carving was made in England. Today, the kiwi is featured on New Zealand’s coat of arms, coins, and sports team logos. The New Zealand national rugby league team is nicknamed the Kiwis.