Okarito Brown Kiwi
Encyclopedia
The Okarito Kiwi, Apteryx rowi, also known as the Rowi or Okarito Brown Kiwi, is a member of the Kiwi
Kiwi
Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...

 family Apterygidae, described as new to science
Bird species new to science
This article describes bird species new to science since 1900. Prior to the 20th century, and indeed into its early decades, the pace of discovery of new species was fast; during this period, with numerous collecting expeditions into species-rich areas not previously visited by western...

 in 2003. The species is part of the Brown Kiwi complex, and is morphologically
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 very similar to other members of that complex. It is found in a restricted area of the Okarito forest on the West Coast
West Coast, New Zealand
The West Coast is one of the administrative regions of New Zealand, located on the west coast of the South Island, and is one of the more remote and most sparsely populated areas of the country. It is made up of three districts: Buller, Grey and Westland...

 of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

's South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

, and has a population of about only 300 birds. Some Okarito Brown Kiwis may live up to 100 years.

Taxonomy

The Okarito Kiwi is a monotypic species. Their genus name Apteryx stems from the Greek "without wings". This bird is a ratite
Ratite
A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...

 and has similarities to the others (Emu
Emu
The Emu Dromaius novaehollandiae) is the largest bird native to Australia and the only extant member of the genus Dromaius. It is the second-largest extant bird in the world by height, after its ratite relative, the ostrich. There are three subspecies of Emus in Australia...

, Ostrich
Ostrich
The Ostrich is one or two species of large flightless birds native to Africa, the only living member of the genus Struthio. Some analyses indicate that the Somali Ostrich may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a...

, Rhea
Rhea (bird)
The rheas are ratites in the genus Rhea, native to South America. There are two existing species: the Greater or American Rhea and the Lesser or Darwin's Rhea. The genus name was given in 1752 by Paul Möhring and adopted as the English common name. Möhring's reason for choosing this name, from the...

, Cassowary
Cassowary
The cassowaries are ratites, very large flightless birds in the genus Casuarius native to the tropical forests of New Guinea, nearby islands and northeastern Australia. There are three extant species recognized today...

). Its sternum
Sternum
The sternum or breastbone is a long flat bony plate shaped like a capital "T" located anteriorly to the heart in the center of the thorax...

 has no keel, its wings are minimal, and it has no preen gland. Its palate
Palate
The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...

 is also distinctive, and its feathers have no barbules or aftershaft. Other features that are similar to only the other kiwi
Kiwi
Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...

s is a weak gizzard
Gizzard
The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized stomach constructed of thick, muscular walls is used for grinding up food; often rocks are...

 and no tail, only a pygostyle
Pygostyle
Pygostyle refers to a number of the final few caudal vertebrae fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these....

.

Range and habitat

The Okarito Brown Kiwi lives in the Okarito forest on the West Coast of New Zealand's South Island. On the 29th of June 2010, three breeding pairs were released onto Blumine Island
Blumine Island
Blumine Island, or Oruawairua in the Māori language, is in the Marlborough Sounds in the South Island of New Zealand.Blumine Island is approx and is mostly hill country. It is the site of a scenic reserve meaning anyone can visit the island...

 as part of a breeding program.

Reproduction

The female can lay up to three eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

, each in a different nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...

. Both the male and the female incubate the eggs. The egg is very large, as it weighs 20% of the female's weight (as in all kiwis). Most pairs are monogamous throughout their lives.

Status and conservation

Its conservation status has been set as "nationally critical". Conservation efforts such as Operation Nest Egg and the stoat control regime have been partially successful in restoring the Rowi population. However, the rowi is still in a fragile stage of existence. Predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

, mainly from imported animals such as stoats, is still the biggest threat to the Rowi. The South Okarito Forest was designated a kiwi sanctuary in 2000.
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