23-16 million years ago, early Miocene.
The Riversleigh Cockatoo was about the size of the modern Galah. One of many birds in the Miocene forests, the Riversleigh Cockatoo probably specialised in cracking the hard nuts of rainforest trees to obtain the nutritious kernels inside.
Today, Australia is home to more than 50 parrot species. The Riversleigh Cockatoo is most closely related to the group of small white cockatoos that includes the corellas - Little Corella, Long-billed Corrella.
A fossilised beak of the Riversleigh Cockatoo was found at Riversleigh in north-western Queensland.
Did you know?
Most other Miocene bird fossil deposits in Australia are dominated by waterbird fossils. Riversleigh is important because it has many land-based birds such as the Riversleigh Cockatoo, as well as waterbirds.