Kiwis: Apterygidae

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KIWIS: Apterygidae

BROWN KIWI (Apteryx australis): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

Kiwis (KEE-weez) are about the size of a chicken. They range in height from 14 to 22 inches (35 to 55 centimeters) and weigh 2.6 to 8.6 pounds (1.2 to 3.9 kilograms). They have brown and black hair-like feathers, no tail, and four toes.

Kiwis are the smallest of a group of birds called ratites, flightless birds that have a flat breastbone rather than a keeled (curved) breastbone like birds of flight. They have a simplified wing bone structure, strong legs, and no feather vanes, the barbs that make up each feather, making it unnecessary to oil the feathers. Consequently, they have no preen gland, which normally contains preening oil.

GEOGRAPHIC RANGE

Kiwis are found in various locations in New Zealand and on nearby islands, including Stewart Island. The North Island brown kiwi is the most widespread, with an estimated 30,000 in the wild.

HABITAT

Most kiwis prefer subtropical and temperate forests, including coniferous and deciduous forests, grassland, scrubland, and farmland. Two varieties live in the higher elevations, the Stewart Island brown kiwi and great spotted kiwi.

DIET

Kiwis are primarily insectivores, meaning they eat mainly insects. Their diet includes earthworms, beetles, snails, caterpillars, centipedes, spiders, cockroaches, praying mantises, snails, locusts, crickets, grasshoppers, and insect larvae. They will eat some plant material, such as fallen fruit and berries, but only rarely. Kiwis find most of their food by scent, using the highly sensitive nostrils located at the end of their beak.

BEHAVIOR AND REPRODUCTION

Kiwis are nocturnal, meaning they are most active at night. They live in burrows they dig several weeks before they are used. This allows the regrowth of moss and other vegetation that camouflages (KAM-uh-flaj-uhs) the burrow. A pair of kiwis can have up to one hundred burrows within their established territory, which is generally 61.75 acres (25 hectares) but can be as much as 120 acres (48 hectares).

Kiwis are shy, night birds with a keen sense of smell. They are monogamous, meaning they mate with only one partner. They pair up for at least two or three breeding seasons and sometimes for life. The female usually digs a nest in the ground where she lays one or two large eggs, weighing about 1 pound (0.45 kilograms) each.

KIWIS AND PEOPLE

The kiwi is the national symbol of New Zealand and an important draw for tourists. Its image is found on New Zealand stamps, coins, and corporate logos, including the now-defunct Kiwi Air. It is used to promote a variety of commercial products.

CONSERVATION STATUS

The IUCN lists the brown kiwi as Endangered, facing a very high risk of extinction, and three kiwi species as Vulnerable, facing a high risk of extinction: the little spotted kiwi, great spotted kiwi, and brown kiwi.

UNIQUE KIWI PARENTING

Little spotted kiwis have a way of raising their young that is unique among kiwis. The male incubates the eggs for seventy days. Once the chicks hatch, the female helps in the rearing. Adult little spotted kiwis do not feed their young but the males and females escort their chicks into the forest to search for food, mainly berries and worms. With other species, the chicks are left on their own to find food after hatching. The little spotted kiwi is one of the most endangered of all kiwis. Human destruction of their habitat is the primary reason for their decline. Once common on the mainland of New Zealand, only about 1,000 remain off the mainland on Tiritiri Matangi Island, Red Mercury Island, Mana Island, Long Island, Hen Island, and Kapiti Island. They also survive on the Kaori Kiwi Reserve in Wellington as part of the government's captive breeding program.

About 1,000 years ago, there were an estimated twelve million kiwis in New Zealand. That number dropped to five million by 1930 due to hunting by humans and animals, such as dogs, cats, and stoats, which are small weasels. As of 2004, there are only about 50,000 to 60,000 kiwis left in the wild and that number is dwindling each year. In 1991, the New Zealand government began a kiwi recovery program that includes establishing kiwi sanctuaries.

BROWN KIWI (Apteryx australis): SPECIES ACCOUNT

Physical characteristics: There are two subspecies (or types) of brown kiwi, the southern tokoeka kiwi, also called the Stewart Island brown kiwi, and Haast tokoeka kiwi, also known as the Haast brown kiwi. The southern variety is larger, with a stout body, powerful claws for digging, and loose brown and black feathers. It has a long beak with nostrils at the end for smelling. The Haast tokoeka kiwi is smaller with a plump, round body and small head with little eyes. It has a long beak that curves slightly downward with nostrils at the end.

Brown kiwis range in size from 18 to 22 inches (45 to 55 centimeters) with females weighing 4.6 to 8.5 pounds (2.1 to 3.9 kilograms) and males weighing 3.6 to 6.1 pounds (1.6 to 2.8 kilograms). They have short wings that end with a claw.

Geographic range: The Haast tokoeka kiwi is found in only a few mountainous areas of North Island New Zealand where the winters are harsh. The southern tokoeka kiwi is found on preserves in Fiordland and Westland on South Island and on Stewart Island.

Habitat: The Haast tokoeka kiwi lives in the coniferous pine forests of North Island while the southern tokoeka kiwi lives in subtropical, temperate, deciduous, and coniferous forests and shrublands.

Diet: Brown kiwis are mainly insectivores, meaning they eat mostly insects. Their diet includes earthworms, beetles, snails, caterpillars, centipedes, spiders, cockroaches, praying mantises, locusts, crickets, grasshoppers, and insect larvae.

Behavior and reproduction: Brown kiwis are nocturnal, meaning they are most active at night. During the day, they sleep in dens or burrows. They are monogamous, meaning they mate with only one partner during one or more breeding seasons. They live in pairs and are territorial, meaning they are protective of an area they consider home and claim exclusively for themselves. A brown kiwi pair's territory ranges from 12 to 106 acres (5 to 43 hectares).

During the breeding season, the female lays one or two eggs in a nest made in thick vegetation. The male incubates the eggs, meaning he sits on them to keep them warm so the embryos inside can develop and hatch. The incubation period is about ninety days.

Brown kiwis and people: The brown kiwi has no economic significance for humans. It is a protected species in New Zealand and the government has established a recovery program for them, including captive breeding and establishing sanctuaries.

Conservation status: The brown kiwi is listed by the IUCN as Vulnerable. There are an estimated 30,000 southern tokoeka kiwis in the wild and only 200 to 300 Haast tokoeka kiwis in a few select areas of New Zealand. ∎

FOR MORE INFORMATION

Books:

Davies, S. J. J. F., et al. Bird Families of the World. Vol. 8, Ratites and Tinamous: Tinamidae, Rheidae, Dromaiidae, Casuariidae, Apterygidae, Struthionidae. Oxford, U.K.: Oxford University Press, 2002.

Elwood, Ann, and John B. Wexo. Ostriches, Emus, Rheas, Kiwis, and Cassowaries (Zoo Books). Mankato, MN: Creative Education, 2000.

Harris, Timothy. Ostriches, Rheas, Cassowaries, Emus, and Kiwis. New York: Beech Publishing House, 1997.

Lockyer, John, et al. The Kiwi. Auckland, New Zealand: Reed Publishing (NZ) Ltd., 2002.

Talbot-Kelly, Chloe. Collins Birds of New Zealand. Auckland, New Zealand: HarperCollins New Zealand, 1997.

Periodicals:

De Roy, Tui. "New Zealand's Bizarre Un-Bird." International Wildlife (May–June 1997): 38–43.

Grzelewski, Derek. "Night Belongs to the Kiwi—It May Look Fuzzy and Adorable but This New Zealand Bird is One Tough Customer." Smithsonian (March 2000): 76.