[DoctorMELON] Sign of frustration or hormonal behavior? Why parrot vigorously ring the bell?

It is summer here, and it was too hot to fall asleep for me, so I stayed the night in the living room leaving MELON sleeping in the bedroom. The very next morning, he was wide awake searching for his dad. I guess he shows his negative feeling by ringing the bell, this time the bell is for complaining about this.
Btw, I guess it seems quite alright for him sleeping somewhere else by himself. Because he didn't ring the bell when he woke up in the living room leaving his dad in the bedroom.