Apteryx australis

Geographic Range

Apteryx australis , commonly known as brown kiwis, is located in the Australian biogeographic region. They are endemic to New Zealand, and reside on North Island (in Northland and Taranaki), South island (in Fiordland and Westland), and Stewart Island.

Apteryx australis is considered by some authors to be made up of two, distinct species, corresponding to the previously recognized subspecies A. australis mantelli - now A. mantelli , and A. australis australis and A. australis lawryi - both retained within A. australis . North Island brown kiwis ( A. mantelli ) are the most common kind of kiwi, found only on the North Island of New Zealand. Apteryx australis includes populations on Stewart Island ( A. a. lawryi ) and South Island ( A. a. australis ), including populations in the Haast range and the fiordlands. Populations in the Haast range (Haast tokoekas) may represent a distinct species as well.

The population of brown kiwis found in Okarito forests on the western coast of the South Island was recently recognized as a distinct species, Apteryx rowi , Okarito brown kiwis or rowis. It is thought that this species is made up of only 200 individuals currently.

• Biogeographic Regions
• australian australian
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Brown kiwis live in subtropical and temperate forests and grasslands. They prefer to live in large, dark forest areas, which allow camouflage for the birds as they sleep during the day. In undisturbed habitats, kiwis create burrows under stones, banks of streams, or in soft flat open ground. In disturbed areas, these birds have had to adapt to human presence by establishing burrows in rough farmland under logs and shrubs.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• scrub forest scrub forest

• Other Habitat Features
• agricultural agricultural

Physical Description

Brown kiwis are members of the flightless ratite group ( Struthioniformes ). They are unique in their small size and adaptations to forest floor life. These birds are roughly the size of a chicken, with the female being slightly larger. They range in size from 45 to 54 cm long, and weigh from 2.8 to 3.5 kg. They are brownish grey in color with long, soft feathers that look and feel very fur-like. Their skin is tough and they have whiskers at the base of their bill used for touch. This is especially important for these birds because they have small eyes and poor vision. These birds do not have a tail and their 5 cm long wings prevent them from flying. Brown kiwis have powerful legs and can run quickly. The nostrils are at the end of their long bills and they have a keen sense of smell. The birds thrust their bill into the ground, gather the food, and beat the prey on the ground before they consume it. Other characteristics include heavy bone marrow, a body temperature lower than most other birds, and underdeveloped pectoral muscles. Brown kiwis have body temperatures of 38 degrees Celsius.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike
• female larger

Reproduction

Brown kiwis meet in nesting burrows every few days and call to each other at night to begin mating. This ritual occurs between March and June. The relationship is volatile and physical with the females primarily being the dominant one. They are monogamous unless a “better” mate comes along.

• Mating System
• monogamous monogamous

Brown kiwis breed throughout the year but only lay one egg at a time. A second egg might be laid four to six weeks after the first one. The eggs are unique because of their size relative to the adult bird's mass. Brown kiwi eggs are one-third of the female's mass, making them the largest eggs (relative to mass) of any bird. Incubation period lasts up to eleven weeks and the chicks are ready to leave the nest in approximately six to ten days. Females reach sexual maturity on average between the ages of three and five. Males reach this sexual maturity in approximately 18 months.

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Female brown kiwis dig out the nest and deposit the kiwi eggs, which are smooth and are either ivory or light green in color. After the eggs are laid, males take over incubation and nest maintenance until the eggs hatch. During this time males lose one-third of their weight. After hatching, the chicks do not rely on parents for food. They survive from the copious amount of yolk in their belly. Kiwi chicks venture out of the burrow soon after hatching, although there have been reports of chicks being near their parents for up to a year. Because kiwi chicks are slow, small (weighting only 275 grams and being five inches), and unable to respond to predators, few survive to twelve months old. After that time, they reach a size that enables them to escape most predators.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male

Lifespan/Longevity

The expected lifespan of brown kiwis after their first twelve months of their life is approximately 20 years in the wild. When in captivity, these birds usually live to be 30 years old, but some have lived up to 40 years.

Behavior

Brown kiwis are described as "honorary mammals" because they have some characteristics that are similary to many mammals. They are nocturnal, rely heavily on a sense of smell, and have feathers that resemble fur. Brown kiwis are shy and mainly solitary, but they will travel in companies of six to twelve. Being nocturnal is beneficial because it reduces competition, they can take advantage of food that is not available during the day, and the darkness brings safety from predators. Brown kiwis will attack if threatened but are more likely to try and escape a threatening interaction. During the day, brown kiwis will hide in their burrows and coil themselves into a ball until nightfall, when they search for food.

• Key Behaviors
• cursorial
• terricolous
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial

Home Range

Their habitat ranges from sea level to areas that are 1,200 meters above ground. Territories range from five to 50 hectares, which is correlated to the quality of the area. Brown kiwis are known to be highly territorial. Once another bird enters their territory, they will cry out a call to warn that bird to leave or else prepare to fight.

Communication and Perception

Brown kiwis communicate through a cry, which sounds like a prolonged whistle slightly ascending and descending. Males make a mournful shriek, "kee-wee," and females have a low hoarse cry. Chicks tend to make a clicking sound. The cry indicates their presence at night, and helps in finding mates. They also congregate in companies from six to twelve. To hear the cry of brown kiwis, click here: http://www.nzbirds.com/birds/sound/brownkiwi2.wav

Kiwis are unusual among birds in having a keen sense of smell. They have an enlarged olfactory bulb.

• Communication Channels
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Brown kiwis are carnivorous, they feed mainly on soil and aquatic invertebrates such as worms, insects, crayfish, amphibians, and eels. They also eat fruit. At night, these birds use their long bills to dig deep into the ground to find creatures living on the ground. After they have caught something, they use their bills to beat the creature on the ground, or on stones to kill it before eating. Cone-shape holes left in the ground after hunting are easy ways to discover their occurrence in an area.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • vermivore

• Animal Foods
• amphibians
• fish
• insects
• terrestrial non-insect arthropods
• mollusks
• terrestrial worms
• aquatic crustaceans

• Plant Foods
• fruit

Predation

Brown kiwis have many introduced predators, although they had few predators before dogs, pigs, cats, brush-tailed possums, and stoats were introduced to New Zealand. Dogs, pigs and cats tend to feed on adult birds. Stoats and cats feed on the young, and possums and stoats destroy kiwi eggs.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Brown kiwis are important predators of invertebrates and may disperse seeds through their fruit eating.

Economic Importance for Humans: Positive

Initially hunted to make cloaks and for food, kiwis, including brown kiwis, are the national symbol of New Zealand. Much pride is taken by displaying the kiwi on things such as the national currency, sports uniforms, road signs and mascots.

• Positive Impacts
• body parts are source of valuable material
• ecotourism ecotourism
• research and education

Economic Importance for Humans: Negative

There are no known adverse affects of brown kiwis on humans.

Conservation Status

Brown kiwis are considered vulnerable by the IUCN. Currently, there are an estimated 27,000 brown kiwis. The primary threat to these birds is predation by introduced mammals. Populations seem to be declining.

Other Comments

The government of New Zealand has declared that if avian flu threatens New Zealand, every kiwi will be vaccinated due to the alarming decrease of kiwis.

Although they are currently only found in New Zealand, fossil evidence has shown ancestors of brown kiwis occurred in the North Hemisphere in the Paleocene and Eocene, 40-70 million years ago.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Smitha Gudipati (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

Attenborough, D. 1998. The Life of Birds . Princeton, New Jersey: Princeton University.

Baker, A., C. Daugherty, R. Colbourne, J. McLennan. 1995. Flightless Brown Kiwis of New Zealand Possess Extremely Subdivided Population Structure and Cryptic Species Like Small Mammals. Proceedings of the National Academy of Sciences , 92: 8254-8258.

Burton, R. 1985. Bird Behavior . New York, New York: Roxby Natural History Limited.

Olliver, N. 2005. "nzbirds" (On-line). North Island brown Kiwi. Accessed November 11, 2006 at http://www.nzbirds.com/birds/kiwinibrown.html .

Tennyson, A., R. Palma, H. Robertson, T. Worthy, B. Gill. 2003. A new species of kiwi (Aves, Apterygiformes) from Okarito, New Zealand. Records of the Auckland Museum , 40: 55-64.

Turbott, E., J. Keulemans. 1967. Buller's Birds of New Zealand . Tokyo: John Weatherhill.

Turbott, F. 1967. A Field Guide To The Birds Of New Zealand . Boston, Ma: The Riverside Press Cambridge.

Williams, G. 1963. Birds of New Zealand . 182 Wakefield Street, Wellington: Publishers of New Zealand Books.

Tourism New Zealand. 2006. The Official Tourism New Zealand Site for Destination New Zealand. Accessed November 08, 2006 at http://www.newzealand.com/travel/about-nz/nature/nature-fauna.cfm .

FONZ. 2006. "Answers to Kiwi Questions" (On-line). Smithsonian National Zoological Park. Accessed November 08, 2006 at http://nationalzoo.si.edu/Animals/Birds/Ask_a_kori_bustard_question/kiwiQandAs.cfm .

Bank of New Zealand Kiwi Recovery™ Trust, Bank of New Zealand, and Department of Conservatio. 2002. "Department of Conservation" (On-line). Save the Kiwi. Accessed October 09, 2006 at http://www.savethekiwi.org.nz/AboutTheBird/KiwiLifeCycle/Mating.htm .

2004. "IUCN Red List of Threatened Species" (On-line). Threatened Species. Accessed October 06, 2006 at http://www.iucnredlist.org/search/details.php/1939/summ .

LA & HA Campbell. 2005. "Kiwi Club (Chemistry & New Zealand)" (On-line). Accessed October 10, 2006 at http://www.chemistry.co.nz/kiwibird.htm .

Data Koncepts. 2006. "Kiwi" (On-line). Kiwi Information. Accessed November 08, 2006 at http://www.mercurybay.co.nz/local/kiwiinfo.html .

CBS. 2006. "New Zealand ready to vaccinate treasured kiwiw against bird flu" (On-line). CBS News. Accessed November 08, 2006 at http://www.cbc.ca/health/story/2006/03/24/kiwi-flu060324.html .

2006. "Wildanimalonline" (On-line). BIRDS. Accessed October 13, 2006 at http://www.wildanimalsonline.com/birds/commonkiwi-brownkiwi.php .

Willowbank Reserve. 2006. "Willowbank" (On-line). Accessed October 10, 2006 at http://www.willowbank.co.nz/kiwi.asp .

2006. "World: Asia-Pacific Kiwis 'freefall' to extinction" (On-line). BBC News. Accessed September 06, 1999 at http://news.bbc.co.uk/2/hi/asia-pacific/449104.stm .

wikimedia. 2006. "wikipedia" (On-line). Kiwi. Accessed October 10, 2006 at http://en.wikipedia.org/wiki/Brown_Kiwi .