Moving Angel Statue

My mother got this as a gift from my sister. She keeps it on a showcase cabinet near the window in the living room. My mom has been telling me that it tends to rotate from facing forward to facing the window. She did not say how long it takes and if it only does so. Or when someone is in the room or not.
I have not had a chance yet to video tape it on the move per say. My father is in the living room alot, during the times I was down this year for local medical appointments. So TV and such was on and he likes to talk.
However if next time I am visiting and alone I will attempt so.

These are pictures of when its facing the window.