Editing Moa (section)

==Behaviour and ecology==
[[File:Moa footprints.jpg|thumb|upright|Preserved footprints of a ''D. novaezealandiae'' found in 1911]]
About eight moa [[fossil trackway|trackway]]s, with fossilised moa footprint impressions in fluvial silts, have been found in the North Island, including [[Waikanae]] Creek (1872), [[Napier, New Zealand|Napier]] (1887), [[Manawatū River]] (1895), [[Marton, New Zealand|Marton]] (1896), [[Palmerston North]] (1911) (see photograph to left), [[Rangitīkei River]] (1939), and under water in [[Lake Taupō]] (1973). Analysis of the spacing of these tracks indicates walking speeds between {{convert|3|and|5|km/h|mph|abbr=on}}.<ref name="WH" /> In 2022, an additional trackway was discovered at the entrance of [[Kaipara Harbour]].<ref>{{cite journal |last1=Thomas |first1=Daniel B. |last2=Fleury |first2=Kane |last3=Paterson |first3=Malcolm |last4=Hayward |first4=Bruce W. |last5=Erickson |first5=Ricky-Lee |title=A short trackway of tridactyl fossil footprints discovered in the Kaipara region of the North Island of New Zealand |journal=New Zealand Journal of Geology and Geophysics |date=2 April 2025 |pages=1–15 |doi=10.1080/00288306.2025.2472831|doi-access=free }}</ref>

In 2019, the first known trackway in the South Island was found in a riverbed at [[Kyeburn]], Otago.<ref>{{cite journal |last1=Fleury |first1=Kane |last2=Burns |first2=Emma |last3=Richards |first3=Marcus D. |last4=Norton |first4=Kevin |last5=Read |first5=Stephen |last6=Wesley |first6=Rachel |last7=Ewan Fordyce |first7=R. |last8=Wilcken |first8=Klaus |title=The moa footprints from the Pliocene – early Pleistocene of Kyeburn, Otago, New Zealand |journal=Journal of the Royal Society of New Zealand |date=19 October 2024 |volume=54 |issue=5 |pages=620–642 |doi=10.1080/03036758.2023.2264789|pmc=11459810 }}</ref> A second set of footprints were discovered at [[Pareora]], Canterbury, in 2022.<ref>{{cite news |last1=Srinivasa |first1=Yashas |title=South Canterbury man 'privileged and lucky' after discovering Canterbury's first set of moa footprints |url=https://www.stuff.co.nz/timaru-herald/news/129598240/south-canterbury-man-privileged-and-lucky-after-discovering-canterburys-first-set-of-moa-footprints |access-date=4 May 2025 |work=Stuff |date=17 August 2022}}</ref>

===Diet===
Their diet has been deduced from [[fossil]]ised contents of their [[gizzard]]s<ref>Burrows, et al. (1981)</ref><ref name="autogenerated3">Wood (2007)</ref> and [[coprolite]]s,<ref>Horrocks, et al. (2004)</ref> as well as indirectly through morphological analysis of skull and beak, and [[Isotope analysis|stable isotope analysis]] of their bones.<ref name="WH" /> Moa fed on a range of plant species and plant parts, including fibrous twigs and leaves taken from low trees and shrubs. The beak of ''[[Pachyornis]] elephantopus'' was analogous to a pair of [[secateur]]s, and could clip the fibrous leaves of New Zealand flax (''[[Phormium]] tenax'') and twigs up to at least 8&nbsp;mm in diameter.<ref name="autogenerated3" />

Moa filled the [[ecological niche]] occupied in other countries by large browsing mammals such as [[antelope]] and [[llamas]].<ref name=":1">{{Cite book|title=Ghosts of Gondwana: the history of life in New Zealand|last=Gibbs|first= George W.|date=2006|publisher=Craig Potton Pub|isbn=978-1877333484|location=Nelson, N.Z.|oclc=83611783}}</ref> Some biologists contend that a number of plant species evolved to avoid moa browsing.<ref name=":1" /> Divaricating plants such as ''[[Pennantia corymbosa]]'' (the kaikōmako), which have small leaves and a dense mesh of branches, and ''[[Pseudopanax crassifolius]]'' (the horoeka or lancewood), which has tough juvenile leaves, are possible examples of plants that evolved in such a way. Likewise, it has been suggested that [[heteroblasty]] might be a response to moa browsing.<ref>{{cite journal|last1=Fadzly|first1=N|last2=Jack|first2=C|last3=Schaefer|first3=HM|last4=Burns|first4=KC|title=Ontogenetic colour changes in an insular tree species: signalling to extinct browsing birds?|journal=New Phytologist|year=2009|volume=184|issue=2|pages=495–501|doi=10.1111/j.1469-8137.2009.02926.x|pmid=19674327|bibcode=2009NewPh.184..495F}}</ref>

Like many other birds, moa swallowed gizzard stones ([[gastrolith]]s), which were retained in their muscular [[gizzards]], providing a grinding action that allowed them to eat coarse plant material. This grinding action suggests that moa were not effective seed dispersers, with only the smallest seeds passing through their gut intact.<ref>{{Cite journal |last1=Carpenter |first1=Joanna K. |last2=Wood |first2=Jamie R. |last3=Wilmshurst |first3=Janet M. |last4=Kelly |first4=Dave |date=2018-04-25 |title=An avian seed dispersal paradox: New Zealand's extinct megafaunal birds did not disperse large seeds |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=285 |issue=1877 |pages=20180352 |doi=10.1098/rspb.2018.0352 |issn=0962-8452 |pmc=5936733 |pmid=29669903}}</ref> These stones were commonly smooth rounded quartz pebbles, but stones over {{convert|110|mm|in|0}} long have been found among preserved moa gizzard contents.<ref name="autogenerated3" /> ''Dinornis'' gizzards could often contain several kilograms of stones.<ref name="WH" /> Moa likely exercised a certain selectivity in the choice of gizzard stones and chose the hardest pebbles.<ref>{{cite journal | last1 = Smalley | first1 = I.J. | year = 1979 | title = Moas as rockhounds | journal = Nature | volume = 281 | issue = 5727| pages = 103–104 | doi = 10.1038/281103b0 | bibcode = 1979Natur.281..103S | s2cid = 33405428 }}</ref>

===Reproduction===
[[File:Emeus egg and embryo.jpg|thumb|left|An egg and embryo fragments of ''Emeus crassus'']]
The pairs of species of moa described as ''Euryapteryx curtus'' / ''E.&nbsp;exilis'', ''Emeus huttonii'' / ''E.&nbsp;crassus'', and ''Pachyornis septentrionalis'' / ''P.&nbsp;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.<ref name="Huynen" />

For example, before 2003, three species of ''Dinornis'' were recognised: South Island giant moa (''D.&nbsp;robustus''), North Island giant moa (''D.&nbsp;novaezealandiae''), and slender moa (''D.&nbsp;struthioides''). However, DNA showed that all ''D.&nbsp;struthioides'' were males, and all ''D.&nbsp;robustus'' were females. Therefore, the three species of ''Dinornis'' were reclassified as two species, one each formerly occurring on New Zealand's North Island (''D.&nbsp;novaezealandiae'') and South Island (''D.&nbsp;robustus'');<ref name="Huynen" /><ref>{{Cite journal |last1=Bunce |first1=M. |last2=Worthy |first2=Trevor |author2-link=Trevor Worthy |last3=Ford |first3=T. |last4=Hoppitt |first4=W. |last5=Willerslev |first5=E. |last6=Drummond |first6=A. |last7=Cooper |first7=A. |url=https://www.cs.auckland.ac.nz/~alexei/2003_Bunce_etal.pdf |archive-url=https://web.archive.org/web/20190128092134/https://www.cs.auckland.ac.nz/~alexei/2003_Bunce_etal.pdf |url-status=dead |archive-date=28 January 2019 |title=Extreme reversed sexual size dimorphism in the extinct New Zealand moa Dinornis |journal=Nature |volume=425 |issue=6954 |pages=172–175 |year=2003 |pmid=12968178 |doi=10.1038/nature01871 |bibcode=2003Natur.425..172B|s2cid=1515413 }}</ref> ''D.&nbsp;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-selection|K-selected]], as are many other large endemic New Zealand birds.<ref name="Turvey" /> They are characterised by having a low [[fecundity]] and a long [[wikt:maturation|maturation]] period, taking about 10 years to reach adult size. The large ''Dinornis'' species took as long to reach adult size as small moa species, and as a result, had fast skeletal growth during their juvenile years.<ref name="Turvey" />

No evidence has been found to suggest that moa were colonial nesters. Moa nesting is often inferred from accumulations of eggshell fragments in [[caves]] and rock shelters, little evidence exists of the [[bird nest|nest]]s themselves. 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]]".<ref>Hartree (1999)</ref> 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).<ref name="Wood">Wood, J.R. (2008)</ref> [[Seed]]s and [[pollen]] within moa coprolites found among the nesting material provide evidence that the nesting season was late spring to summer.<ref name="Wood" />

Fragments of moa eggshell are often found in [[archaeological]] sites and [[sand dunes]] around the New Zealand coast. Thirty-six whole moa eggs exist in museum collections and vary greatly in size (from {{convert|120|-|240|mm|in}} in length and {{convert|91|-|178|mm|in}} wide).<ref>Gill, B.J. (2007)</ref> 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.<ref name="Huynen, Leon 2010">Huynen, Leon; Gill, Brian J.; Millar, Craig D.; and Lambert, David M. (2010)</ref>
[[File:The skeleton of female upland moa.JPG|thumb|The skeleton of female upland moa with egg in unlaid position within the pelvic cavity in Otago Museum]]
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."<ref name="Huynen, Leon 2010"/> Despite the bird's extinction, the high yield of DNA available from recovered fossilised eggs has allowed the moa's genome to be sequenced.<ref>Yong, Ed. (2010)</ref>