last time I tried to put at the highest point of the cage but they don even get inside the first time they lay egg on the cage base...When i transfer it to that place than they start to go inside and lay her eggs.....anyway she have already sit on the eggs....But she not fierce leh...last time my other cockatiels are fierce when she sit on the eggs not only sit get into nest box alredy fierce...Meabe mine is tame that she is not so fierce as the wild one...