Жоғалған моа құстары туралы мақала

Extinct order of birds
the extinct New Zealand birds known as moa

Moa (order Dinornithiformes) are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene Holocene, there were nine species (in six genera). The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about while the smallest, the bush moa (Anomalopteryx didiformis), was around the size of a turkey. Estimates of the moa population when Polynesians settled New Zealand circa 1300 vary between 58,000

Moa are traditionally placed in the ratite group.

The word moa is a Polynesian term for domestic fowl. The name was not in common use among the Māori by the time of European contact, likely because the bird it described had been extinct for some time, and traditional stories about it were rare. The earliest record of the name was by missionaries William Williams and William Colenso in January 1838; Colenso speculated that the birds may have resembled gigantic fowl. In 1912, Māori chief Urupeni Pūhara claimed that the moa's traditional name was "te kura" (the red bird).

Moa skeletons were traditionally reconstructed in an upright position to create impressive height, but analysis of their vertebral articulations indicates that they probably carried their heads forward, in the manner of a kiwi. The spine was attached to the rear of the head rather than the base, indicating the horizontal alignment. This would have let them graze on low vegetation, while being able to lift their heads and browse trees when necessary. This has resulted in a reconsideration of the height of larger moa. However, Māori rock art depicts moa or moa like birds (likely geese or adzebills) with necks upright, indicating that moa were more than capable of assuming both neck postures. No records survive of what sounds moa made, though some idea of their calls can be gained from fossil evidence. The trachea of moa were supported by many small rings of bone known as tracheal rings. Excavation of these rings from articulated skeletons has shown that at least two moa genera (Euryapteryx and Emeus) exhibited tracheal elongation, that is, their trachea were up to 1 m (3 ft) long and formed a large loop within the body cavity. Previously, the kiwi, the Australian emu, and cassowary were thought to be most closely related to moa. Although dozens of species were described in the late 19th and early 20th centuries, many were based on partial skeletons and turned out to be synonyms. Currently, 11 species are formally recognised, although recent studies using ancient DNA recovered from bones in museum collections suggest that distinct lineages exist within some of these. One factor that has caused much confusion in moa taxonomy is the intraspecific variation of bone sizes, between glacial and interglacial periods (see Bergmann’s rule and Allen’s rule) as well as sexual dimorphism being evident in several species. Dinornis seems to have had the most pronounced sexual dimorphism, with females being up to 150% as tall and 280% as heavy as males—so much bigger that they were classified as separate species until 2003. A 2009 study showed that Euryapteryx curtus and E. gravis were synonyms. A 2010 study explained size differences among them as sexual dimorphism. A 2012 morphological study interpreted them as subspecies, instead. Analyses of ancient DNA have determined that a number of cryptic evolutionary lineages occurred in several moa genera. These may eventually be classified as species or subspecies; Megalapteryx benhami (Archey) is synonymised with M. didinus (Owen) because the bones of both share all essential characters. Size differences can be explained by a north–south cline combined with temporal variation such that specimens were larger during the Otiran glacial period (the last ice age in New Zealand). Similar temporal size variation is known for the North Island's Pachyornis mappini. Some of the other size variation for moa species can probably be explained by similar geographic and temporal factors. The earliest moa remains come from the Miocene Saint Bathans Fauna. Known from multiple eggshells and hind limb elements, these represent at least two already fairly large sized species.

Significantly less is known about North Island paleofaunas, due to a paucity of fossil sites compared to the South Island, but the basic pattern of moa habitat relationships was the same. and coprolites, as well as indirectly through morphological analysis of skull and beak, and stable isotope analysis of their bones. Some biologists contend that a number of plant species evolved to avoid moa browsing.

The pairs of species of moa described as Euryapteryx curtus / E. exilis, Emeus huttonii / E. crassus, and Pachyornis septentrionalis / P. mappini have long been suggested to constitute males and females, respectively. This has been confirmed by analysis for sex specific genetic markers of DNA extracted from bone material. D. robustus however, comprises three distinct genetic lineages and may eventually be classified as many species, as discussed above. Examination of growth rings in moa cortical bone has revealed that these birds were K selected, as are many other large endemic New Zealand birds. Moa nesting material has also been recovered from rock shelters in the Central Otago region of the South Island, where the dry climate has preserved plant material used to build the nesting platform (including twigs clipped by moa bills). Seeds and pollen within moa coprolites found among the nesting material provide evidence that the nesting season was late spring to summer. The outer surface of moa eggshell is characterised by small, slit shaped pores. The eggs of most moa species were white, although those of the upland moa (Megalapteryx didinus) were blue green. A 2010 study by Huynen et al. found that the eggs of certain species were fragile, only around a millimetre in shell thickness: "Unexpectedly, several thin shelled eggs were also shown to belong to the heaviest moa of the genera Dinornis, Euryapteryx, and Emeus, making these, to our knowledge, the most fragile of all avian eggs measured to date. Moreover, sex specific DNA recovered from the outer surfaces of eggshells belonging to species of Dinornis and Euryapteryx suggest that these very thin eggs were likely to have been incubated by the lighter males. The thin nature of the eggshells of these larger species of moa, even if incubated by the male, suggests that egg breakage in these species would have been common if the typical contact method of avian egg incubation was used."

Studies of accumulated dried vegetation in the pre human mid late Holocene period suggests a low Sophora microphylla or Kōwai forest ecosystem in Central Otago that was used and perhaps maintained by moa, for both nesting material and food. Neither the forests nor moa existed when European settlers came to the area in the 1850s.

Before the arrival of humans, the moa's only predator was the massive Haast's eagle. New Zealand had been isolated for 80 million years and had few predators before human arrival, meaning that not only were its ecosystems extremely vulnerable to perturbation by outside species, but also the native species were ill equipped to cope with human predators. Polynesians arrived sometime before 1300, and all moa genera were soon driven to extinction by hunting and, to a lesser extent, by habitat reduction due to forest clearance. By 1445, all moa had become extinct, along with Haast's eagle, which had relied on them for food. Recent research using carbon 14 dating of middens strongly suggests that the events leading to extinction took less than a hundred years, rather than a period of exploitation lasting several hundred years as previously hypothesised. An expedition in the 1850s under Lieutenant A. Impey reported two emu like birds on a hillside in the South Island; an 1861 story from the Nelson Examiner told of three toed footprints measuring between Tākaka and Riwaka that were found by a surveying party; and finally in 1878, the Otago Witness published an additional account from a farmer and his shepherd. In childhood, Mackenzie saw a large bird that she believed to be a takahē, but after its rediscovery in the 1940s, she saw a picture of it and concluded that she had seen something else. Some authors have speculated that a few Megalapteryx didinus may have persisted in remote corners of New Zealand until the 18th and even 19th centuries, but this view is not widely accepted. Some Māori hunters claimed to be in pursuit of the moa as late as the 1770s; however, these accounts possibly did not refer to the hunting of actual birds as much as a now lost ritual among South Islanders. Whalers and sealers recalled seeing monstrous birds along the coast of the South Island, and in the 1820s, a man named George Pauley made an unverified claim of seeing a moa in the Otago region of New Zealand. and as recently as 2008, Cryptozoologists continue to search for them, but their claims and supporting evidence (such as of purported footprints) have earned little attention from experts and are pseudoscientific. Dieffenbach also refers to a fossil from the area near Mt Hikurangi, and surmises that it belongs to "a bird, now extinct, called Moa (or Movie) by the natives". 'Movie' is the first transcribed name for the bird. In 1839, John W. Harris, a Poverty Bay flax trader who was a natural history enthusiast, was given a piece of unusual bone by a Māori who had found it in a river bank. He showed the fragment of bone to his uncle, John Rule, a Sydney surgeon, who sent it to Richard Owen, who at that time was working at the Hunterian Museum at the Royal College of Surgeons in London. In July 2004, the Natural History Museum in London placed on display the moa bone fragment Owen had first examined, to celebrate 200 years since his birth, and in memory of Owen as founder of the museum. Since the discovery of the first moa bones in the late 1830s, thousands more have been found. They occur in a range of late Quaternary and Holocene sedimentary deposits, but are most common in three main types of site: caves, dunes, and swamps. Bones are commonly found in caves or tomo (the Māori word for doline or sinkhole, often used to refer to pitfalls or vertical cave shafts). The two main ways that the moa bones were deposited in such sites were birds that entered the cave to nest or escape bad weather, and subsequently died in the cave and birds that fell into a vertical shaft and were unable to escape. Moa bones (and the bones of other extinct birds) have been found in caves throughout New Zealand, especially in the limestone/marble areas of northwest Nelson, Karamea, Waitomo, and Te Anau. Moa bones and eggshell fragments sometimes occur in active coastal sand dunes, where they may erode from paleosols and concentrate in 'blowouts' between dune ridges. Many such moa bones antedate human settlement, although some originate from Māori midden sites, which frequently occur in dunes near harbours and river mouths (for example the large moa hunter sites at Shag River, Otago, and Wairau Bar, Marlborough). Densely intermingled moa bones have been encountered in swamps throughout New Zealand. The most well known example is at Pyramid Valley in north Canterbury, where bones from at least 183 individual moa have been excavated, mostly by Roger Duff of Canterbury Museum. Many explanations have been proposed to account for how these deposits formed, ranging from poisonous spring waters to floods and wildfires. However, the currently accepted explanation is that the bones accumulated slowly over thousands of years, from birds that entered the swamps to feed and became trapped in the soft sediment. Many New Zealand and international museums hold moa bone collections. Auckland War Memorial Museum – Tāmaki Paenga Hira has a significant collection, and in 2018 several moa skeletons were imaged and 3D scanned to make the collections more accessible. There is also a major collection in Otago Museum in Dunedin.

The creature has frequently been mentioned as a potential candidate for revival by cloning. Its iconic status, coupled with the facts that it only became extinct a few hundred years ago and that substantial quantities of moa remains exist, mean that it is often listed alongside such creatures as the dodo as leading candidates for de extinction. Preliminary work involving the extraction of DNA has been undertaken by Japanese geneticist Ankoh Yasuyuki Shirota. Interest in the moa's potential for revival was further stirred in mid 2014 when New Zealand Member of Parliament Trevor Mallard suggested that bringing back some smaller species of moa within 50 years was a viable idea. The idea was ridiculed by many, but gained support from some natural history experts.

Heinrich Harder portrayed moa being hunted by Māori in the classic German collecting cards about extinct and prehistoric animals, "Tiere der Urwelt", in the early 1900s. Allen Curnow's poem, "The Skeleton of the Great Moa in the Canterbury Museum, Christchurch" was published in 1943.