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. She claimed that her brother had also seen a moa on another occasion.  A 2010 study explained size differences among them as sexual dimorphism. Similar temporal size variation is known for the North Island's Pachyornis mappini. Excavations of rock shelters in the eastern North Island during the 1940s found moa nests, which were described as "small depressions obviously scratched out in the soft dry pumice". The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.6 m (12 ft) in height with neck outstretched, and weighed about 230 kg (510 lb) while the smallest, the bush moa, was around the size of a turkey. , The creature has frequently been mentioned as a potential candidate for revival by cloning. Our editors will review what you’ve submitted and determine whether to revise the article. …originally included several species of moa, a large bird that was eventually exterminated by the Maori. The feature is associated with deep resonant vocalisations that can travel long distances. Although the larger moas probably became extinct by the end of the 17th century, a few smaller species may have survived into the 19th. However, many modern ornithologists suggest that these features could be advantageous adaptations that have nothing to do with paedomorphism. 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. However, DNA showed that all D. struthioides were males, and all D. robustus were females. This has resulted in a reconsideration of the height of larger moa. , The Oligocene Drowning Maximum event, which occurred about 22 Mya, when only 18% of present-day New Zealand was above sea level, is very important in the moa radiation.  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. In addition, studies of unique growth rings in leg bones of moas have indicated that they grew at an exceptionally slow rate, taking as many as 10 years to reach full size. In Proceedings of the VII International Meeting of the Society of Avian Paleontology and Evolution, ed. According to Maori tradition, moas were swift runners that defended themselves by kicking when cornered.  Some biologists contend that a number of plant species evolved to avoid moa browsing.  Many explanations have been proposed to account for how these deposits formed, ranging from poisonous spring waters to floods and wildfires. Moa were nine species (in six genera) of now-extinct flightless birds endemic to New Zealand. Moa, (order Dinornithiformes), any of several extinct ostrichlike flightless birds native to New Zealand and constituting the order Dinornithiformes. Insights from nineteen years of ancient DNA research on the extinct moa (Aves: Dinornithiformes) of New Zealand", "Ancient DNA reveals elephant birds and kiwi are sister taxa and clarifies ratite bird evolution", "Genomic Support for a Moa-Tinamou Clade and Adaptive Morphological Convergence in Flightless Ratites", "The evolutionary history of the extinct ratite moa and New Zealand Neogene paleogeography", "Regional comparisons of the thickness of moa eggshell fragments (Aves: Dinornithiformes).  Moas likely exercised a certain selectivity in the choice of gizzard stones and chose the hardest pebbles. W.E. , Joel Polack, a trader who lived on the East Coast of the North Island from 1834 to 1837, recorded in 1838 that he had been shown "several large fossil ossifications" found near Mt Hikurangi. Many such moa bones antedate human settlement, although some originate from Maori 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). The 1993 report initially interested the Department of Conservation, but the animal in a blurry photograph was identified as a red deer.