A New Zealand man’s riverside stroll has resulted in what researchers are calling a “mind-blowing” discovery of ancient footprints of a now-extinct giant, flightless bird.

Altogether, seven tracks deemed to belong to a moa, which was only found in New Zealand, were discovered by a local man at a swimming hole. Measuring about 30 centimeters long and 30 centimeters wide (12 inches by 12 inches), the distinct markings are astonishingly preserved and present some of the first evidence of the giant animal living in this particular part of the country.

“This find is significant because it is the first record of verifiable moa footprints from the South Island of New Zealand,” Kane Fleury, Assistant Curator of Natural Sciences at Otago Museum, told IFLScience adding that the sediment in which these slabs are preserved in is fairly old and from a period where there is very little fossil moa material. 

“The age of the sediment is between 1 and 11 million years old which is based on the formations it occurs in, however when the moa walked across those sediments is currently unknown,” he said.

Researchers are able to deduce from the tracks that the bird had relatively large and wide feet with fleshy footpads. The way that the tracks are laid suggests that the moa was walking slowly through the mud and was slightly turning to the right. The moa only fairly recently went extinct about 700 years ago namely due to the arrival of humans on the islands and being hunted by the M?ori, the first settlers in New Zealand.

“By the time Europeans arrived in New Zealand they were extinct,” said Fleury, noting that the largest species of moa could stretch their necks up to about 3.6 meters (12 feet) high and weighed about 230 kilograms (500 pounds). To feed their massive bodies, moa fed on a variety of plants with their sharp beaks. In fact, Fleury notes that many plants in New Zealand have adaptations specifically to deter moa from eating them.

“Like most New Zealand birds they were long-lived and slow to reach sexual maturity. Before humans arrived their only predator was the giant Haast’s Eagle,” he said.

Just last week, Otago Museum staff successfully excavated six of the seven moa footprints after deeming that they would not be protected if left in the river.

“Ironically, it was likely a flood event that originally uncovered the prints from the clay bank. The Kye Burn is a major river course with a large catchment area,” wrote the museum in a statement sent to IFLScience, adding that experts were concerned that another high flow event would destroy the tracks “in the same manner that exposed them.”

Once the tracks are stabilized, researchers plan to organize a hui – a large meeting – with iwi, a local tribe of the M?ori, as well as landowners, regional councils, museum staff, and other parties that were involved in the discovery. Afterward, Fleury says his team will conduct research and place the tracks on a temporary display for the public to see.