Zebra that is rolling its head

[ac12]

I have a zebra that just started doing something odd.
It is rolling/waving its head from side to side.

Hard to describe but think of a flag waving, the head will "wave" from the bottom of the neck moving up to the head, but just in the left/right direction, no forward/back movement.
I've not seen any other finch do that funny thing, and it only does it once in a while. And that is what triggered my question, the odd behavior that I had not seen before.

I tried to search and did not find anything. But also did not know what to use as a search term.

thanks

[poohbear]

Try the Lady Gouldian site and use the word 'twirling'