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85-474: Elephant birds are extinct flightless birds belonging to the order Aepyornithiformes that were native to the island of Madagascar . They are thought to have become extinct around 1000 AD, likely as a result of human activity. Elephant birds comprised three species, one in the genus Mullerornis , and two in Aepyornis . Aepyornis maximus is possibly the largest bird to have ever lived, with their eggs being

170-771: A molecular clock analysis estimating the split around 27 million years ago. Molecular dating estimates that the divergence between Aepyornithidae and Mullerornithidae occurred approximately 30 Ma, close to the Eocene-Oligocene boundary, a period of marked global cooling and faunal turnover in the Northern Hemisphere. Up to 10 or 11 species in the genus Aepyornis have been described, but the validity of many have been disputed, with numerous authors treating them all in just one species, A. maximus . Up to three species have been described in Mullerornis . Recent work has restricted

255-425: A pourquoi story explaining features of New Zealand birds. Owen portrays the kiwi as nobly sacrificing its wings and flight in order to protect the trees from depredation by ground-dwelling creatures, and thereby winning its unique renown. Owen's story is sometimes described as "A Maori Legend". It has been recorded as a children's story, published as a book, was made into an animated film in 1980, set to music for

340-419: A bird, and are the only birds with nostrils at the end of their long beaks. Kiwi eat small invertebrates, seeds, grubs, and many varieties of worms. They also may eat fruit, small crayfish, eels and amphibians. Because their nostrils are located at the end of their long beaks, kiwi can locate insects and worms underground using their keen sense of smell, without actually seeing or feeling them. This sense of smell

425-854: A claimed territory selected for large size and cursoriality in Tertiary ancestors of ratites. Temperate rainforests dried out throughout the Miocene and transformed into semiarid deserts, causing habitats to be widely spread across the growingly disparate landmasses. Cursoriality was an economic means of traveling long distances to acquire food that was usually low-lying vegetation, more easily accessed by walking. Traces of these events are reflected in ratite distribution throughout semiarid grasslands and deserts today. Gigantism and flightlessness in birds are almost exclusively correlated due to islands lacking mammalian or reptilian predators and competition. However, ratites occupy environments that are mostly occupied by

510-412: A diverse number of mammals. It is thought that they first originated through allopatric speciation caused by breakup of the supercontinent Gondwana . However, later evidence suggests this hypothesis first proposed by Joel Cracraft in 1974 is incorrect. Rather ratites arrived in their respective locations via a flighted ancestor and lost the ability to fly multiple times within the lineage. Gigantism

595-648: A joint 1080 poison operation undertaken by DOC and the Animal Health Board in Tongariro Forest in 2006, 32 kiwi chicks were radio-tagged. 57% of the radio-tagged chicks survived to adulthood. Efforts to protect kiwi have had some success, and in 2017 two species were downlisted from endangered to vulnerable by the IUCN. In 2018 the Department of Conservation released its current Kiwi Conservation Plan. In 2000,

680-633: A kiwi that had been caught in a possum trap. Extensive monitoring shows that kiwi are not at risk from the use of biodegradable 1080 poison. Introduced mammalian predators , namely stoats, dogs, ferrets, and cats, are the principal threats to kiwi. The biggest threat to kiwi chicks is stoats, while dogs are the biggest threat to adult kiwi. Stoats are responsible for approximately half of kiwi chick deaths in many areas through New Zealand. Young kiwi chicks are vulnerable to stoat predation until they reach about 1–1.2 kg (2.2–2.6 lb) in weight, at which time they can usually defend themselves. Cats also to

765-415: A large (~48%) grazing component to their diets, similar to that of the living Rhea americana , while the other species ( A. maximus , Mullerornis modestus ) were probably browsers . It has been suggested that Aepyornis straightened its legs and brought its torso into an erect position in order to browse higher vegetation. Some rainforest fruits with thick, highly sculptured endocarps , such as that of

850-545: A length of approximately 26–40 centimetres (10–16 in) and a width of 19–25 centimetres (7.5–9.8 in). The largest Aepyornis eggs are on average 3.3 mm ( 1 ⁄ 8  in) thick, with an estimated weight of approximately 10.5 kilograms (23 lb). Eggs of Mullerornis were much smaller, estimated to be only 1.1 mm ( 3 ⁄ 64  in) thick, with a weight of about 0.86 kilograms (1.9 lb). The large size of elephant bird eggs means that they would have required substantial amounts of calcium, which

935-409: A lesser extent prey on kiwi chicks. These predators can cause large and abrupt declines in populations. In particular, dogs find the distinctive strong scent of kiwi irresistible and easy to track, such that they can catch and kill kiwi in seconds. Motor vehicle strike is a threat to all kiwi where roads cross through their habitat. Badly set possum traps often kill or maim kiwi. Habitat destruction

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1020-502: A limited number of times per year. High parental involvement denotes the necessity for choosing a reliable mate. In a climatically stable habitat providing year-round food supply, a male's claimed territory signals to females the abundance of resources readily available to her and her offspring. Male size also indicates his protective abilities. Similar to the emperor penguin, male ratites incubate and protect their offspring anywhere between 85 and 92 days while females feed. They can go up to

1105-480: A long history of coexistence between elephant birds and humans; however, these conclusions conflict with more commonly accepted evidence of a much shorter history of human presence on the island and remain controversial. The oldest securely dated evidence for humans on Madagascar dates to the mid-first millennium AD. A 2021 study suggested that elephant birds, along with the Malagasy hippopotamus species, became extinct in

1190-418: A lower-case k and, being a word of Māori origin, normally stays as kiwi when pluralised . The genus name Apteryx is derived from Ancient Greek 'without wing': a- ( ἀ- ), 'without' or 'not'; ptéryx ( πτέρυξ ), 'wing'. Although it was long presumed that the kiwi was closely related to the other New Zealand ratites, the moa , recent DNA studies have identified its closest relative as

1275-409: A male and female kiwi tend to live their entire lives as a monogamous couple. During the mating season, June to March, the pair call to each other at night, and meet in the nesting burrow every three days. These relationships may last for up to 20 years. They are unusual among other birds in that, along with some raptors, they have a functioning pair of ovaries . (In most birds and in platypuses ,

1360-462: A more efficient use of energy in adulthood. The name "ratite" comes from the Latin ratis , raft, a vessel with no keel . Their flat sternum is distinct from the typical sternum of flighted birds because it lacks a keel, like a raft. This structure is the place where flight muscles attach and thus allow for powered flight. However, ratite anatomy presents other primitive characters meant for flight, such as

1445-554: A parachute apparatus to help the bird slow down. Wings are hypothesized to have played a role in sexual selection in early ancestral ratites and were thus maintained. This can be seen today in both the rheas and ostriches. These ratites utilize their wings extensively for courtship and displays to other males. Sexual selection also influences the maintenance of large body size, which discourages flight. The large size of ratites leads to greater access to mates and higher reproductive success . Ratites and tinamous are monogamous and mate only

1530-718: A population of A. rowi in New Zealand under no environmental stress had ocular lesions in one or both eyes. The same experiment examined three specific specimens that showed complete blindness and found them to be in good physical standing outside of ocular abnormalities. A 2018 study revealed that the kiwi's closest relatives, the extinct elephant birds , also shared this trait despite their great size. Unlike virtually every other palaeognath , which are generally small-brained by bird standards, kiwi have proportionally large encephalisation quotients . Hemisphere proportions are even similar to those of parrots and songbirds , though there

1615-431: A result of habitat intrusion by predators, including humans. In areas of New Zealand where introduced predators have been removed, such as sanctuaries, kiwi are often seen in daylight. They prefer subtropical and temperate podocarp and beech forests, but they are being forced to adapt to different habitat, such as sub-alpine scrub, tussock grassland, and the mountains. Kiwi have a highly developed sense of smell, unusual in

1700-494: A similar nocturnal lifestyle. The optic lobes of Mullerornis were also reduced, but to a lesser degree, suggestive of a nocturnal or crepuscular lifestyle. A. maximus had relatively larger olfactory bulbs than A. hildebrandti , suggesting that the former occupied forested habitats where the sense of smell is more useful while the latter occupied open habitats. A 2022 isotope analysis study suggested that some specimens of Aepyornis hildebrandti were mixed feeders that had

1785-416: A week without eating and survive only off fat stores. The emu has been documented fasting for as long as 56 days. If no continued pressures warrant the energy expenditure to maintain the structures of flight, selection will tend towards these other traits. In penguins , wing structure is maintained for use in locomotion underwater. Penguins evolved their wing structure to become more efficient underwater at

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1870-399: Is another major threat to kiwi; restricted distribution and small size of some kiwi populations increases their vulnerability to inbreeding. Research has shown that the combined effect of predators and other mortality (accidents, etc.) results in less than 5% of kiwi chicks surviving to adulthood. The Māori traditionally believed that kiwi were under the protection of Tāne Mahuta , god of

1955-412: Is due to a highly developed olfactory chamber and surrounding regions. It is a common belief that the kiwi relies solely on its sense of smell to catch prey but this has not been scientifically observed. Lab experiments have suggested that A. australis can rely on olfaction alone but is not consistent under natural conditions. Instead, the kiwi may rely on auditory and/or vibrotactile cues. Once bonded,

2040-758: Is instead thought to be an adaptation for precocity , enabling kiwi chicks to hatch mobile and with yolk to sustain them for two and half weeks. The large eggs would be safe in New Zealand's historical absence of egg-eating ground predators, while the mobile chicks would be able to evade chick-eating flying predators. Lice in the genus Apterygon and in the subgenus Rallicola ( Aptericola ) are exclusively ectoparasites of kiwi species. Nationwide studies show that only around 5–10% of kiwi chicks survive to adulthood without management. As of 2018 over 70% of kiwi populations are unmanaged. However, in areas under active pest management, survival rates for North Island brown kiwi can be far higher. For example, prior to

2125-426: Is known from an intact egg, around 80–90% of the way through incubation before it died. This skeleton shows that even at this early ontogenetic stage that the skeleton was robust, much more so than comparable hatchling ostriches or rheas, which may suggest that hatchlings were precocial . The eggs of Aepyornis are the largest known for any amniote , and have a volume of around 5.6–13 litres (12–27 US pt),

2210-416: Is likely because penguins have well-developed pectoral muscles for hunting and diving in the water. For ground-feeding birds, a cursorial lifestyle is more economical and allows for easier access to dietary requirements. Flying birds have different wing and feather structures that make flying easier, while flightless birds' wing structures are well adapted to their environment and activities, such as diving in

2295-432: Is little evidence of human hunting of elephant birds. Humans may have utilized elephant bird eggs. Introduced diseases ( hyperdisease ) have been proposed as a cause of extinction, but the plausibility for this is weakened due to the evidence of centuries of overlap between humans and elephant birds on Madagascar. Flightless birds Many domesticated birds, such as the domestic chicken and domestic duck , have lost

2380-405: Is long, pliable and sensitive to touch, and their eyes have a reduced pecten . Their feathers lack barbules and aftershafts , and they have large vibrissae around the gape . They have 13 flight feathers , no tail and a small pygostyle . Their gizzard is weak and their caecum is long and narrow. The eye of the kiwi is the smallest relative to body mass in all avian species, resulting in

2465-427: Is no evidence of similarly complex behaviour. Before the arrival of humans in the 13th century or earlier, New Zealand's only endemic mammals were three species of bat , and the ecological niches that in other parts of the world were filled by creatures as diverse as horses, wolves and mice were taken up by birds (and, to a lesser extent, reptiles, insects and gastropods). The kiwi's mostly nocturnal habits may be

2550-411: Is not a requirement for flightlessness. The kiwi do not exhibit gigantism, along with tinamous , even though they coexisted with the moa and rheas that both exhibit gigantism. This could be the result of different ancestral flighted birds arrival or because of competitive exclusion. The first flightless bird to arrive in each environment utilized the large flightless herbivore or omnivore niche, forcing

2635-431: Is often why flightlessness coincides with body mass. By reducing large pectoral muscles that require a significant amount of overall metabolic energy, ratites decrease their basal metabolic rate and conserve energy. A study looking at the basal rates of birds found a significant correlation between low basal rate and pectoral muscle mass in kiwis. On the contrary, flightless penguins exhibit an intermediate basal rate. This

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2720-431: Is that until the arrival of humans roughly a thousand years ago, there were no large mammalian land predators in New Zealand; the main predators of flightless birds were larger birds. Ratites belong to the superorder Palaeognathae , which include the volant tinamou , and are believed to have evolved flightlessness independently multiple times within their own group. Some birds evolved flightlessness in response to

2805-411: Is the smallest of the elephant birds, with a body mass of around 80 kilograms (180 lb), with its skeleton much less robustly built than Aepyornis . A. hildebrandti is thought to have had a body mass of around 230–285 kilograms (507–628 lb). Estimates of the body mass of Aepyornis maximus span from around 275 kilograms (606 lb) to 700–1,000 kilograms (1,500–2,200 lb) making it one of

2890-401: Is usually taken from a reservoir in the medullary bone in the femurs of female birds. Possible remnants of this tissue have been described from the femurs of A. maximus. It is widely believed that the extinction of elephant birds was a result of human activity. The birds were initially widespread, occurring from the northern to the southern tip of Madagascar . The late Holocene also witnessed

2975-964: The Berlin Zoo has seven, Walsrode Bird Park has one, the Avifauna Bird Park in the Netherlands has three, the San Diego Zoo has five, the San Diego Zoo Safari Park has one, the National Zoo in Washington, DC has eleven, the Smithsonian Conservation Biology Institute has one, and the Columbus Zoo and Aquarium has three. In 2023, Zoo Miami apologized for mistreating a kiwi, after footage of visitors patting

3060-645: The Department of Conservation set up five kiwi sanctuaries focused on developing methods to protect kiwi and to increase their numbers. A number of other mainland conservation islands and fenced sanctuaries have significant populations of kiwi, including: North Island brown kiwi were introduced to the Cape Sanctuary in Hawke's Bay between 2008 and 2011, which in turn provided captive-raised chicks that were released back into Maungataniwha Native Forest. Sanctuaries for kiwi are also referred to as 'kōhanga sites' from

3145-639: The Holocene (no more than 11,000 years ago). Extinct species are indicated with a cross (†). A number of species suspected, but not confirmed to be flightless, are also included here. Longer-extinct groups of flightless birds include the Cretaceous patagopterygiformes , hesperornithids , the Cenozoic phorusrhacids ("terror birds") and related bathornithids , the unrelated eogruids , geranoidids , gastornithiforms , and dromornithids (mihirungs or "demon ducks"), and

3230-621: The Kerguelen Islands , and an ostrich egg found floating in the Timor Sea in the early 1990s. Like the ostrich , rhea , cassowary , emu , kiwi and extinct moa , elephant birds were ratites; they could not fly, and their breast bones had no keel . Because Madagascar and Africa separated before the ratite lineage arose, elephant birds has been thought to have dispersed and become flightless and gigantic in situ . More recently, it has been deduced from DNA sequence comparisons that

3315-518: The moa in New Zealand. In 1851 the genus Aepyornis and species A. maximus were scientifically described in a paper presented to the Paris Academy of Sciences by Isidore Geoffroy Saint-Hilaire , based on bones and eggs recently obtained from the island, which resulted in wide coverage in the popular presses of the time, particularly due to their very large eggs. Two whole eggs have been found in dune deposits in southern Western Australia , one in

3400-426: The order Apterygiformes . The five extant species fall into the family Apterygidae ( / ˌ æ p t ə ˈ r ɪ dʒ ə d iː / ) and genus Apteryx ( / ˈ æ p t ər ɪ k s / ). Approximately the size of a domestic chicken , kiwi are the smallest ratites (which also include ostriches , emus , rheas , cassowaries and the extinct elephant birds and moa ). DNA sequence comparisons have yielded

3485-501: The plotopterids . Apterygidae Apteryx haastii Great spotted kiwi Apteryx owenii Little spotted kiwi Apteryx rowi Okarito brown kiwi Apteryx australis Southern brown kiwi Apteryx mantelli North Island brown kiwi Stictapteryx Iredale & Mathews, 1926 Kiwi Verheyen, 1960 Pseudapteryx Lydekker 1891 Kiwi ( / ˈ k iː w iː / KEE -wee ) are flightless birds endemic to New Zealand of

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3570-489: The 17th century. Étienne de Flacourt , a French governor of Madagascar during the 1640s and 1650s, mentioned an ostrich-like bird, said to inhabit unpopulated regions, although it is unclear whether he was repeating folk tales from generations earlier. In 1659, Flacourt wrote of the "vouropatra – a large bird which haunts the Ampatres and lays eggs like the ostriches; so that the people of these places may not take it, it seeks

3655-692: The 1930s (the Scott River egg) and one in 1992 (the Cervantes egg); both have been identified as Aepyornis maximus rather than Genyornis newtoni , an extinct giant bird known from the Pleistocene of Australia. It is hypothesized that the eggs floated from Madagascar to Australia on the Antarctic Circumpolar Current . Evidence supporting this is the finding of two fresh penguin eggs that washed ashore on Western Australia but may have originated in

3740-601: The Kiwis. A kiwi has featured on the reverse side of three New Zealand coins: the one florin (two-shilling) coin from 1933 to 1966, the twenty-cent coin from 1967 to 1990, and the one-dollar coin since 1991. In currency trading the New Zealand dollar is often referred to as "the kiwi". A song, "Sticky Beak the Kiwi", with words by Bob Edwards and music by Neil Roberts, was recorded in 1961, sung by Julie Nelson (aged 14) and accompanied by

3825-654: The Miocene such as Proapteryx further supports the view that ratites did not diversify in response to vicariance . Gondwana broke apart in the Cretaceous and their phylogenetic tree does not match the process of continental drift . Madagascar has a notoriously poor Cenozoic terrestrial fossil record, with essentially no fossils between the end of the Cretaceous ( Maevarano Formation ) and the Late Pleistocene. Complete mitochondrial genomes obtained from elephant birds eggshells suggest that Aepyornis and Mullerornis are significantly genetically divergent from each other, with

3910-770: The Māori word for 'nest' or 'nursery'. Operation Nest Egg is a programme run by the BNZ Save the Kiwi Trust—a partnership between the Bank of New Zealand , the Department of Conservation and the Royal Forest and Bird Protection Society . Kiwi eggs and chicks are removed from the wild and hatched and/or raised in captivity until big enough to fend for themselves—usually when they weigh around 1200 grams (42 ounces). They are then returned to

3995-613: The Satins and the Don Bell Orchestra of Whangārei . A Christmas song, it portrays Sticky Beak as insisting on pulling Santa Claus's sleigh when distributing presents south of the equator. "How the Kiwi Lost its Wings" is a fable written by broadcaster Alwyn Owen in 1963. It uses elements of Māori mythology, such as Tāne Mahuta , and the World War I symbol of cowardice, white feathers , in

4080-657: The UK and the US, the symbol became more widely known. During the First World War, the name "Kiwis" for New Zealand soldiers came into general use, and a giant kiwi (now known as the Bulford kiwi ) was carved on the chalk hill above Sling Camp in England. Usage has become so widespread that all New Zealanders overseas and at home are now commonly referred to as " Kiwis ". The kiwi has since become

4165-635: The ability to fly for extended periods, although their ancestral species, the red junglefowl and mallard , respectively, are capable of extended flight. A few particularly bred birds, such as the Broad Breasted White turkey , have become totally flightless as a result of selective breeding ; the birds were bred to grow massive breast meat that weighs too much for the bird's wings to support in flight. Flightlessness has evolved in many different birds independently, demonstrating repeated convergent evolution. There were families of flightless birds, such as

4250-413: The ability to fly. They are, however, weak fliers and are incapable of traveling long distances by air. Although selection pressure for flight was largely absent, the wing structure has not been lost except in the New Zealand moas. Ostriches are the fastest running birds in the world and emus have been documented running 50 km/h. At these high speeds, wings are necessary for balance and serving as

4335-404: The absence of predators, for example on oceanic islands . Incongruences between ratite phylogeny and Gondwana geological history indicate the presence of ratites in their current locations is the result of a secondary invasion by flying birds. It remains possible that the most recent common ancestor of ratites was flightless and the tinamou regained the ability to fly. However, it is believed that

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4420-557: The best-known national symbol for New Zealand, and the bird is prominent in the coat of arms, crests and badges of many New Zealand cities, clubs and organisations. At the national level, the red silhouette of a kiwi is in the centre of the roundel of the Royal New Zealand Air Force . The kiwi is featured in the logo of the New Zealand Rugby League , and the New Zealand national rugby league team are nicknamed

4505-450: The bristly, hair-like, two-branched feathers. While most adult birds have bones with hollow insides to minimise weight and make flight practicable, kiwi have marrow , like mammals and the young of other birds. With no constraints on weight due to flight requirements, brown kiwi females carry and lay a single egg that may weigh as much as 450 g (16 oz). Like most other ratites, they have no uropygial gland ( preen gland). Their bill

4590-761: The closest living relatives of elephant birds are New Zealand kiwi , though the split between the two groups is deep, with the two lineages being estimated to have diverged from each other around 54 million years ago. Placement of Elephant birds within Palaeognathae, after: Struthionidae (ostriches) Rheidae (rheas) Tinamidae (tinamou) † Dinornithiformes (moa) Apterygidae (kiwis) † Aepyornithiformes (elephant birds) Casuariiformes (emu, cassowary) The ancestors of elephant birds are thought to have arrived in Madagascar well after Gondwana broke apart. The existence of possible flying palaeognathae in

4675-452: The 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 their remaining habitat is well protected in large forest reserves and national parks. At present,

4760-453: The cost of their efficiency in the air. The only known species of flightless bird in which wings completely disappeared was the gigantic, herbivorous moa of New Zealand , hunted to extinction by humans by the 15th century. In moa, the entire pectoral girdle is reduced to a paired scapulocoracoid , which is the size of a finger. Many flightless birds are extinct ; this list shows species that are either still extant or became extinct in

4845-550: The currently undispersed and highly threatened forest coconut palm ( Voanioala gerardii ), may have been adapted for passage through ratite guts and consumed by elephant birds, and the fruit of some palm species are indeed dark bluish-purple (e.g., Ravenea louvelii and Satranala decussilvae ), just like many cassowary-dispersed fruits, suggesting that they too may have been eaten by elephant birds. Elephant birds are suggested to have grown in periodic spurts rather than having continuous growth. An embryonic skeleton of Aepyornis

4930-410: The egg, except for the great spotted kiwi, A. haastii , in which both parents are involved. The incubation period is 63–92 days. Producing the huge egg places significant physiological stress on the female; for the thirty days it takes to grow the fully developed egg, the female must eat three times her normal amount of food. Two to three days before the egg is laid there is little space left inside

5015-440: The end of their long beak to detect prey before they 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. The Māori language word kiwi is generally accepted to be "of imitative origin" from the call . However, some linguists derive

5100-473: The evolution of flightlessness hypothesized intraspecific competition selected for a reduced individual energy expenditure, which is achieved by the loss of flight. Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost . Flight is the most costly type of locomotion exemplified in the natural world. The energy expenditure required for flight increases proportionally with body size, which

5185-601: The extinct elephant bird of Madagascar , and among extant ratites, the kiwi is more closely related to the emu and the cassowaries than to the moa. Research published in 2013 on an extinct genus, Proapteryx , known from the Miocene deposits of the Saint Bathans Fauna , found that it was smaller and probably capable of flight, supporting the hypothesis that the ancestor of the kiwi reached New Zealand independently from moas, which were already large and flightless by

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5270-493: The extinction of other Malagasy animals, including several species of Malagasy hippopotamus , two species of giant tortoise ( Aldabrachelys abrupta and Aldabrachelys grandidieri ), the giant fossa , over a dozen species of giant lemurs , the aardvark-like animal Plesiorycteropus , and the crocodile Voay . Several elephant bird bones with incisions have been dated to approximately 10,000 BC which some authors suggest are cut marks, which have been proposed as evidence of

5355-439: The female for her stomach and she is forced to fast. It was believed that the large eggs were a trait of much larger moa -like ancestors, and that kiwi retained large eggs as an evolutionarily neutral trait as they became smaller. However, research in the early 2010s suggested that kiwi were descended from smaller flighted birds that flew to New Zealand and Madagascar, where they gave rise to kiwi and elephant birds. The large egg

5440-421: The forest. They were used as food and their feathers were used for kahu kiwi —ceremonial cloaks. Today, while kiwi feathers are still used, they are gathered from birds that die naturally, through road accidents, or predation, and from captive birds. Kiwi are no longer hunted and some Māori consider themselves the birds' guardians. In 1813, George Shaw named the genus Apteryx in his species description of

5525-402: The fusion of wing elements, a cerebellar structure, the presence of a pygostyle for tail feathers, and an alula on the wing. These morphological traits suggest some affinities to volant groups. Palaeognathes were one of the first colonizers of novel niches and were free to increase in abundance until the population was limited by food and territory. A study looking at energy conservation and

5610-418: The greatest threat to their survival is predation by invasive mammalian predators. The vestigial wings are so small as to be invisible under their bristly, hair-like, two-branched feathers. Kiwi eggs are one of the largest in proportion to body size (up to 20% of the female's weight) of any order of bird in the world. Other unique adaptations of kiwi, such as short and stout legs and using their nostrils at

5695-514: The interval 800-1050 AD (1150–900 years Before Present ), based on the timing of the latest radiocarbon dates. The timing of the youngest radiocarbon dates co-incided with major environmental alteration across Madagascar by humans changing forest into grassland, probably for cattle pastoralism , with the environmental change likely being induced by the use of fire. This reduction of forested area may have had cascade effects, like making elephant birds more likely to be encountered by hunters, though there

5780-406: The largest birds ever, alongside Dromornis stirtoni and Pachystruthio dmanisensis . Females of A. maximus are suggested to have been larger than the males, as is observed in other ratites. Examination of brain endocasts has shown that both A. maximus and A. hildebrandti had greatly reduced optic lobes , similar to those of their closest living relatives, the kiwis, and consistent with

5865-510: The largest known for any amniote . Elephant birds are palaeognaths (whose flightless representatives are often known as ratites ), and their closest living relatives are kiwi (found only in New Zealand), suggesting that ratites did not diversify by vicariance during the breakup of Gondwana but instead convergently evolved flightlessness from ancestors that dispersed more recently by flying. Elephant birds have been extinct since at least

5950-504: The later arrivals to remain smaller. In environments where flightless birds are not present, it is possible that after the K/T Boundary there were no niches for them to fill. They were pushed out by other herbivorous mammals . New Zealand had more species of flightless birds (including the kiwi , several species of penguins , the takahē , the weka , the moa, and several other extinct species ) than any other such location. One reason

6035-475: The loss of flight is an easier transition for birds than the loss and regain of flight, which has never been documented in avian history. Moreover, tinamou nesting within flightless ratites indicates ancestral ratites were volant and multiple losses of flight occurred independently throughout the lineage. This indicates that the distinctive flightless nature of ratites is the result of convergent evolution. Two key differences between flying and flightless birds are

6120-425: The most lonely places." There has been speculation, especially popular in the latter half of the 19th century, that the legendary roc from the accounts of Marco Polo was ultimately based on elephant birds, but this is disputed. Between 1830 and 1840, European travelers in Madagascar saw giant eggs and eggshells. British observers were more willing to believe the accounts of giant birds and eggs because they knew of

6205-536: The nocturnal bird under bright lights caused outrage in New Zealand. The kiwi as a symbol first appeared in the late 19th century in New Zealand regimental badges. It was later featured in the badges of the South Canterbury Battalion in 1886 and the Hastings Rifle Volunteers in 1887. Soon after, the kiwi appeared in many military badges; and in 1906, when Kiwi Shoe Polish was widely sold in

6290-502: The now-extinct Phorusrhacidae , that evolved to be powerful terrestrial predators. Taking this to a greater extreme, the terror birds (and their relatives the bathornithids ), eogruids , geranoidids , gastornithiforms , and dromornithids (all extinct) all evolved similar body shapes – long legs, long necks and big heads – but none of them were closely related. Furthermore, they also share traits of being giant, flightless birds with vestigial wings, long legs, and long necks with some of

6375-867: The number of elephant bird species to three, with two in Aepyornis , one in Mullerornis . All elephant birds are usually placed in the single family Aepyornithidae, but some authors suggest Aepyornis and Mullerornis should be placed in separate families within the Aepyornithiformes, with the latter placed into Mullerornithidae. Elephant birds were large sized birds (the largest reaching 3 metres (9.8 ft) tall in normal standing posture) that had vestigial wings, long legs and necks, with small heads relative to body size, which bore straight, thick conical beaks that were not hooked. The tops of elephant bird skulls display punctuated marks, which may have been attachment sites for fleshy structures or head feathers. Mullerornis

6460-430: The ocean. Species with certain characteristics are more likely to evolve flightlessness. For example, species that already have shorter wings are more likely to lose flight ability. Some species will evolve flatter wings so that they move more efficiently underwater at the cost of their flight. Additionally, birds that undergo simultaneous wing molt, in which they replace all of the feathers in their wings at once during

6545-638: The ratites, although they are not related. Divergences and losses of flight within ratite lineage occurred right after the K-Pg extinction event wiped out all non-avian dinosaurs and large vertebrates 66 million years ago. The immediate evacuation of niches following the mass extinction provided opportunities for Palaeognathes to distribute and occupy novel environments. New ecological influences selectively pressured different taxa to converge on flightless modes of existence by altering them morphologically and behaviorally. The successful acquisition and protection of

6630-500: The right ovary never matures, so that only the left is functional. ) Kiwi eggs can weigh up to one-quarter the weight of the female. Usually, only one egg is laid per season. The kiwi lays one of the largest eggs in proportion to its size of any bird in the world, so even though the kiwi is about the size of a domestic chicken, it is able to lay eggs that are about six times the size of a chicken's egg. The eggs are smooth in texture, and are ivory or greenish white. The male incubates

6715-513: The smaller wing bones of flightless birds and the absent (or greatly reduced) keel on their breastbone, which anchors muscles needed for wing movement. Adapting to a cursorial lifestyle causes two inverse morphological changes to occur in the skeleto-muscular system: the pectoral apparatus used to power flight is paedorphically reduced while peramorphosis leads to enlargement of the pelvic girdle for running. Repeated selection for cursorial traits across ratites suggests these adaptions comprise

6800-408: The smallest visual field as well. The eye has small specialisations for a nocturnal lifestyle, but kiwi rely more heavily on their other senses (auditory, olfactory, and somatosensory system ). The sight of the kiwi is so underdeveloped that blind specimens have been observed in nature, showing how little they rely on sight for survival and foraging. In an experiment, it was observed that one-third of

6885-554: The southern brown kiwi, which he called "the southern apteryx". Captain Andrew Barclay of the ship Providence provided Shaw with the specimen. Shaw's description was accompanied by two plates, engraved by Frederick Polydore Nodder ; they were published in volume 24 of The Naturalist's Miscellany . In 1851, London Zoo became the first zoo to keep kiwi. The first captive breeding took place in 1945. As of 2007 only 13 zoos outside New Zealand hold kiwi. The Frankfurt Zoo has 12,

6970-480: The time kiwi appeared. There are five known species of kiwi, with a number of subspecies. A. haastii A. owenii A. australis A. rowi A. mantelli Relationships in the genus Apteryx Their adaptation to a terrestrial life is extensive: like all the other ratites ( ostrich , emu , rhea and cassowary ), they have no keel on the sternum to anchor wing muscles. The vestigial wings are so small that they are invisible under

7055-414: The wild. An Operation Nest Egg bird has a 65% chance of surviving to adulthood—compared to just 5% for wild-hatched and -raised chicks. The tool is used on all kiwi species except little spotted kiwi . In 2004, anti-1080 activist Phillip Anderton posed for the New Zealand media with a kiwi he claimed had been poisoned. An investigation revealed that Anderton lied to journalists and the public. He had used

7140-404: The word from Proto-Nuclear Polynesian * kiwi , which refers to Numenius tahitiensis , the bristle-thighed curlew , a migratory bird that winters in the tropical Pacific islands. With its long decurved bill and brown body, the curlew resembles the kiwi. So when the first Polynesian settlers arrived, they may have applied the word kiwi to the newfound bird. The bird's name is spelled with

7225-562: The year, are more likely to evolve flight loss. A number of bird species appear to be in the process of losing their powers of flight to various extents. These include the Zapata rail of Cuba , the Okinawa rail of Japan , and the Laysan duck of Hawaii . All of these birds show adaptations common to flightlessness, and evolved recently from fully flighted ancestors, but have not yet completely given up

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