Kiwi ( KEE-wee) or kiwis are flightless birds endemic to New Zealand of the genus Apteryx and family Apterygidae . Approximately the size of a domestic chicken, kiwi are by far the smallest living ratites (which also include ostriches, emus, rheas, tinamous and cassowaries). DNA sequence comparisons have yielded the surprising conclusion that kiwi are much more closely related to the extinct Malagasy elephant birds than to the moa with which they shared New Zealand. There are five recognised species, four of which are currently listed as vulnerable, and one of which is near-threatened. All species have been negatively affected by historic deforestation but currently the remaining large areas of their forest habitat are well protected in reserves and national parks. At present, the greatest threat to their survival is predation by invasive mammalian predators. The kiwi's egg is one of the largest in proportion to body size (up to 20% of the female's weight) of any species of bird in the world. Other unique adaptations of kiwi, such as their hairlike feathers, short and stout legs, and using their nostrils at the end of their long beak to detect prey before they ever see it, have helped the bird to become internationally well-known. The kiwi is recognised as an icon of New Zealand, and the association is so strong that the term Kiwi is used internationally as the colloquial demonym for New Zealanders.