DNA detective work has found a simple explanation to a long-standing mystery surrounding New Zealand's earliest domestic chooks.
A study by Kiwi and Australian researchers, published today, draws on radio-carbon dating and DNA sequencing technology to clarify why chicken bones have been found in pre-historic Maori middens when there was little archeological reason for them to be there.
Polynesian voyagers who colonised islands across the Pacific between the 11th and 13th centuries were known to have spread many plants and foods, including taro, bottle gourd, paper mulberry, pigs, rats and chickens.
But the discovery of ancient chicken bones in New Zealand pits didn't fit the picture, as there was a conspicuous absence of pre-historic chicken remains in Polynesia's cooler, sub-tropic and temperate southern islands.
They'd been found in Easter Island and Hawaii, but not in New Zealand, or the Chatham, Auckland, Kermadec and Norfolk Islands over pre-European times.
So how was it that some happened to be found here before European colonists arrived?
Were they brought here by the first Polynesian settlers, but then lost to disease, predation or competition?
Or had there been no need to keep the birds, given the smorgasbord of flightless species already roaming the country?
Perhaps the bones had been put there in more recent times and been confusingly mixed in with the ancient material?
Although chicken bones have been dug up from middens in several places throughout the country, including potentially archaic sites, their pre-historic presence had never been critically examined - until now.
In the new study, led by Dr Jamie Wood of Landcare Research, researchers focused on bones in three sites on the northern coast of the South Island, which were ideal because they also contained material and bones of moa and other large birds that became extinct within 200 years of initial human settlement.
DNA sequencing and radio-carbon dating analysis confirmed the bones were still New Zealand's earliest-known chicken remains.
But they backed another, more simpler theory: it may not have been Maori who brought them here.
Two of the bones pre-dated regular European visits to New Zealand, which happened from 1803 onwards, yet overlapped with the arrival of Captain James Cook's second voyage between 1773 and 1774.
Therefore, the study authors said, they were likely to be chickens liberated during that voyage.
"Our results support the idea that chickens were introduced to New Zealand by Europeans, and provide new insights into Maori uptake and integration of resources introduced during the early post-European period," they said.
The concluded the findings demonstrated that all of the bones were deposited during the early era of contact between Europeans and Maori.
"This finding strongly supports the hypotheses that chickens were either not brought to New Zealand by the first Polynesian settlers, or did not persist for very long following their introduction, due to the abundance of large native animals that could easily be hunted."
However, sources of large native animals had become depleted by the time Captain Cook introduced chickens in 1773, after which chickens became readily integrated into Maori livelihoods, and were moved around New Zealand by Maori at this time, they said.
"The fact that chickens were not introduced to New Zealand soon after the 15th century extinction of megafauna, such as occurred in Tonga, provides compelling evidence for the idea that Maori had lost the ability/knowledge for long-distance inter-island voyaging by this time."
The study, involving Landcare Research, Auckland University, the University of Adelaide and Canterbury Museum, has been published today in the journal Royal Society Open Science.
3D scanning preserves ancient artefacts
Meanwhile, researchers at Canterbury University are using modern 3D-printing technology to preserve and study rare classical antiquities, many dating back more than three millennia.
A close inspection of the university's priceless collection of fragile antique objects has been made possible thanks to collaboration between university academics Dr Don Clucas and Dr Paul Docherty and Logie Collection curators Terri Elder and Penny Minchin-Garvin.
A selection of ancient objects have been scanned and accurately reproduced to be used in the university's mechanical engineering teaching programme this semester.
3D scanning, which allows antiquities to be replicated cheaply, has been used at the university for two years, but it's only been recently targeted at the ancient items.
They include a Babylonian terracotta tablet that was made around 1700BC and lists individuals who have been granted plots of land.
Inscriptions on both sides of the tablet used a phonetic and syllabic script called "Cuneiform", made by pressing a stylus made of reed onto the wet clay.
"Cuneiform tablets deteriorate over time and as with everything else it is a case of dust to dust," said Professor Victor Parker, a classics expert at the university.
"So anything that can be done to replicate tablets in their three-dimensional form before they crumble is extremely important.
"Also, such replicas can be used for teaching purposes without risking increasingly fragile originals."
Another cup dated at 525BCE has also been scanned and printed.
"The project has been very exciting as it has allowed a new dimension of tactile interaction with the replicas of antiquities that would not be possible with the real thing," said Docherty, a mechanical engineering lecturer who started the project.
"In the future, we hope to increase the number of scanned antiquities and put 3D representations of the collection online."