A Timaru woman watched the clay banks for four years, and moa bones turned up on her beach walks

Pippa Yates walks St Andrews Beach, south of Timaru, with her eyes on the ground. On walks one day after another she found bones that experts at the South Canterbury Museum have confirmed came from the extinct moa. The museum's director says the site may date back as far as 120,000 years.

"I knew as soon as I saw them that they were bones," she said. She knew because of the porosity, a texture unlike wood worn by the sea. The wear was not like that of cow or sheep bones either. She went back the next day, and the day after, and each walk turned up more.

The search had begun about four years earlier. Yates and her family had heard of an earlier find in the district: moa footprints and bones at nearby Pareora in 2022, the first moa footprints recorded in Canterbury. From then on, the family walked the beach looking for more.

They now have about half a bucket. Some pieces are large and intact, which Yates said she had not expected. The bones are soaking in plain water in the family kitchen. The family cleans them together in sessions of about an hour, copying the slow washing the beach itself would have given them.

Museum director Philip Howe places the site in the Late Pleistocene. That means these birds lived and died long before the first Polynesian settlers arrived around 1300 CE. Once people came, moa disappeared within about 150 years.

The moa were a strange group of birds. They had no wing bones at all, not even the small leftover ones that kiwi and emus still have. In some species the females were much larger than the males, so much larger that scientists at first counted them as separate species. Ancient DNA studies corrected the mistake in 2003. The first person to identify a moa from its remains was the anatomist Richard Owen. In 1839, working in London from a single fragment of thigh bone, he concluded that a large bird had once lived in New Zealand. The scientific story of the moa has always been told through pieces like the ones now drying in a Timaru kitchen.

The clearest specimens will go to the South Canterbury Museum. There, a fragment of foot bone will be used to make a digital, life-size model for visitors. The family may keep a few of the larger bones and try to fit them together. The smallest fragments will go into specimen jars for Yates's daughter to take to kindergarten and school.

Palaeontologist Dr Hamish Campbell expects more to be found. "A lot of people don't know what they're walking over," he said.

Pippa Yates is one of the people who do.