In 2008, a pair of ancient avian leg bones were discovered at St Bathans, a former mining town in New Zealand known for its rich fossil deposits dating back to the Miocene era. The bones were large—so large that paleontologists assumed they came from a bird of prey. And so the fossils “went into the eagle pile,” Suzanne Hand, a paleontologist at the University of New South Wales in Sydney, tells Cara Giaimo of the New York Times.
But when Ellen Mather, a graduate student researching eagles, took a fresh look at the bones earlier this year, she realized that experts’ previous assessment had been wrong. This prompted a re-analysis of the remains, and a new report published in Biology Letters reveals that the bones belonged not to an eagle, but to the largest parrot known to science.
Upon re-examining the fossils, it became clear to researchers that the bird, which roamed New Zealand around 19 million years ago, was indeed a very big parrot. They compared the leg bones to a variety of bird skeletons held at the South Australian Museum, and to images of bird specimens on the website of the Smithsonian National Museum of Natural History. The team observed a series of features that can be uniquely attributed to psittaciformes, the avian order that includes parrots.
New Zealand is no stranger to hulking avian species. Within the isolated environment of the island, which large land predators could not reach, birds evolved to huge sizes and, in some cases, lost their ability to fly. There was the moa, a flightless bird that stretched to a height of seven feet, and the Haast’s eagle, an enormous predator that hunted the moa. Giant geese and adzebills scuttled along the forest floor. These species, along with half of New Zealand’s avian taxa, have gone extinct since humans’ arrival on the island. But the nation is still home to the largest extant parrot, the flightless kākāpō.
And yet, despite New Zealand’s history of hefty birds, researchers were surprised by the size of the newly discovered parrot. Its large tibiotarsi, or drumsticks, indicated that the bird stood around three feet high—tall enough “to pick the belly button lint out of your belly button,” Michael Archer, a paleontologist at the University of New South Wales and co-author of the new study, tells Jenny Howard of National Geographic. The creature’s weight clocked in at around 15 pounds, more than double that of the chunky kākāpō.
Some have dubbed the bird “Squawkzilla,” but the study authors formally named it Heracles inexpectatus—“Heracles” after the powerful hero of Greek mythology, and “inexpectatus” to reflect the surprising nature of the discovery.
Heracles inexpectatus was likely unable to fly, and much of its diet may have come from fruits and seeds on the forest floor. But researchers suspect the bird also ate meat. Today, New Zealand’s kea parrots are known to attack sheep, digging through skin and muscle to reach the fat around the kidneys. And these birds are considerably smaller than Heracles inexpectatus. The ancient creature “no doubt [had] a massive parrot beak that could crack wide open anything it fancied,” Archer says, adding that Heracles inexpectatus “may well have dined on more than conventional parrot foods, perhaps even other parrots.”
According to Giaimo of the Times, the study authors plan to return St Bathans this year. Past excavations at the site have turned up a plethora of ancient creatures, among them many bird species, and the researchers believe that more landmark avian discoveries will be made in the future.
“We have been excavating these fossil deposits for 20 years, and each year reveals new birds and other animals,” Worthy says. “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.”