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Abstract.
Interest in ratites has necessitated a review of available information on the unique endangered kiwi (Apteryx spp.). Five different species of kiwis, endemic to the three islands of New Zealand, are recognized by the Department of Conservation, New Zealand, according to genetic and biological differences: the North Island Brown Kiwi (Apteryx mantelli), Okarito Brown Kiwi/Rowi (A. rowi), Tokoeka (A. australis), Great Spotted Kiwi/Roroa (A. haastii), and Little Spotted Kiwi (A owenii). As predators were found to be the main reason for declining kiwi numbers, predator control is a main objective of management techniques to prevent kiwis becoming extinct in New Zealand. Further considerations include captive breeding and release, and establishment of kiwi sanctuaries. Body size and bill measurements are different between species and genders within species. Kiwis have the lowest basal rates of metabolism compared with all avian standards. A relative low body temperature (38 °C), burrowing, a highly developed sense of smell, paired ovaries in females, and a low growth rate, separate kiwis from other avian species. Kiwis have long-term partnerships. Females lay an egg that is approximately 400% above the allometrically expected value, with an incubation period of 75-85 days. Kiwis mainly feed on soil invertebrate, with the main constituent being earthworms, and are prone to parasites and diseases found in other avian species. It can be concluded that kiwis present a biological rarity, with several features more characteristic of small mammals than birds.
Key words: kiwi, taxonomy, conservation, reproduction, nutrition
Introduction
Kiwis (Order Struthioniformes, family Apterygidae) are endemic to the three major islands of New Zealand. Contrary to expectation, phylogenetic analysis shows that kiwis are more closely related to Australian (emus) and African (ostriches) ratites than to moas. The latter are an extinct group of 11 ratite species that lived during the Pleistocene era in New Zealand (Cooper et al. 1992).
Apart from their highly distinctive taxonomic status and conservation significance, kiwis are incorporated in the New Zealand culture. They are the unofficial national emblem of New Zealand, and recognized by Maoris as natural treasures to be treated as sacred. Kiwi is the name by whom all New Zealanders are known (Herbert &Daugherty 2002).
Interest in ratites in recent years has increased. Mostly because of the potential of ostriches,...