Rocking cockatiel

by Rose
(NSW)

Hello I have a female cockatiel.She is a very spoilt little girl and has the run of the house. The only time she is inside of her cage is at bed time. I think she is around one years of age.

She has a little cardboard box on the lounge room floor that she loves to play in we call it her cubbyhouse. But the last few days she stays in it for hours and rocks from side to side. Is this a mating thing,we have no other birds.

Hope someone can explain to me what is going on. Thankyou