23-16 million years ago, early Miocene.
Special ankle joints allowed Flexiraptor to bend its feet not just forwards, like most birds, but also backwards and sideways, to reach animals hiding in tree hollows and crevices.
Did you know?
Two living hawks bend their feet in a similar way to Flexiraptor. Neither live in Australia nor are they closely related to Flexiraptor. This is an example of convergent evolution - unrelated animals faced with a similar problem independently develop (converge on) the same solution to that problem.