World’s largest parrot was a metre tall and lived 19 million years ago

Life 7 August 2019
Heracles inexpectatus lived in New Zealand
Heracles inexpectatus lived in New Zealand

Dr Brian Choo, Flinders University

Palaeontologists working in New Zealand have discovered the first evidence of giant parrots, which they believe lived 19 million years ago.

An analysis of two “drumstick” bones, or tibiotarsi, found at a site on the South Island indicate the bird, named Heracles inexpectatus, grew to around one metre tall and weighed seven kilograms.

“It’s a new example of the propensity of islands to generate weird and wacky animals,” says Trevor Worthy of Flinders University, Australia.


The bird is likely to have been flightless, like several other giant flightless birds known to have evolved on islands. These include the extinct dodo, a giant pigeon that lived on Mauritius.

New Zealand was also once home to nine species of moa, a now-extinct group of large birds resembling ostriches and emus, and it is thought that H. inexpectatus would have lived alongside these. While moa typically eat leaves, the giant parrot likely ate fruits and nuts.

The structure of the bird’s bones suggests it was closely related to the kakapo, a large, flightless parrot that still lives in New Zealand today. H. inexpectatus may have moved in a similar way to its smaller relative. “Given the tibiotarsus is very-thick walled we think this indicates that the bird spent a lot of time of the ground and likely had no powered flight. But it may have been able to glide downhill as a kakapo can do after climbing a tree,” says Worthy.

New Zealand has been a hotspot for bird evolution – including many flightless species – due to a lack of predatory mammals. But Worthy says that a three-metre-long, land-dwelling ancestor of the crocodile would probably have hunted the giant parrot.

A giant eagle, around the same size as the adult parrot, may have preyed on younger birds.

The bones were unearthed at St Bathans on South Island, a site that is rich in fossil remains. At least 40 different species of birds have been excavated there so far, and Worthy expects many more species to be discovered there.

Journal reference: Biology Letters, DOI: 10.1098/rsbl.2019.0467

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