https://www.youtube.com/watch?v=t0KT-pec6Cw
As per you tube video, this is the only video I have ever seen to show this.
The other day while hunching down to eye level with my ornate pac in his cage, I caught him doing it!!! I couldn't believe it. I tried to get a video of it but by the time I started filming he stopped
Was very cool to see him do it though, not sure what triggered that.