Ellen Mather knew something wasn't quite right with one of the fossils she was looking at.
A reconstruction of the giant parrot Heracles inexpectatus. Photo: Dr Brian Choo / Flinders University.
The PhD student at Flinders University in Adelaide is researching the fossils of eagles and hawks from Australia and New Zealand.
Dating back as far as 24 million years ago, to as recently as the last few hundred thousand years, not much is known about the birds, or how they relate to today's species.
Ms Mather was given some bones for her project that were thought to belong to a large eagle.
They came from St Bathans in Central Otago.
"One day I was going over them, comparing them to some specimens I had of living eagles today, such as the wedged tail eagle from Australia, and as I was comparing them I noticed that they looked really different from how eagles are supposed to look," she said.
"The fossils lacked certain features that all eagles should have, so I realised pretty quickly that this fossil wasn't from an eagle at all but something quite different."
The fossil Ms Mather was examining was from the bird's leg bone, near where it connects with the foot.
In the birds she looks at, there is usually a bridge of bone across a canal that muscle tendon goes through.
"But the fossil from St Bathans, this bridge was completely absent, instead there was just two ridges on either side of the canal."
St Bathans. Photo: 123RF
Ms Mather knew then that she wasn't looking at an eagle.
"I went back to my supervisor, Trevor Worthy, and brought it to his attention. He took it away to try and figure out what they were - he was able to find out that they actually belonged to a giant parrot."
That giant parrot now has an official name, Heracles inexpectatus, and an appropriate nickname, "Squawkzilla".
It's also made headlines around the world.
The prehistoric bird stood one metre tall and weighed in at about seven kilograms.
That's double the size of the previous record holder for the world's largest parrot, the kākāpō.
Ms Mather said it was pretty thrilling to have been part of such a major scientific discovery.
"At the time I didn't realise that it would be so significant, but it's exciting to have been part of that process."
Heracles inexpectatus was found in fossils dating back as many as 19 million years ago.
Flinders University Associate Professor Trevor Worthy said no-one had ever discovered an extinct giant parrot anywhere until now.
"New Zealand is well known for its giant birds. Not only moa dominated avifaunas, but giant geese and adzebills shared the forest floor, while a giant eagle ruled the skies," he said.
"We have been excavating these fossil deposits for 20 years, and each year reveals new birds and other animals. While Heracles is one of the most spectacular birds we have found, no doubt there are many more unexpected species yet to be discovered in this most interesting deposit."