I wanted to see whether our bird is just particularly naughty or whether this is normal for cockatiels. Our previous one was blind so never had a destructive streak.
In 2 years he has chewed through telephone, stereo, headphone and Sky wires and has stripped the plastic off about two feet of thick cabling revealing the bare wires inside. He has gnawed all the edging off the mantelpiece and destroyed an antique clock. He has worked out how to lift photographs from frames to chew down them and we have recently discovered him pulling the threads of wool from the carpet!
It's not as if he doesn't have lots of attention, he spents 80% of his time on our heads and shoulders and is free to roam the house. Despite all the destruction, we do love his spirit though!!
Oh dear! Looks as if we have about 15 years of this still to come!!! Since writing the original post he's broken the cooker extractor fan by chewing through the cabling and all our books have nibbled edges. He's lucky we love him!
Have a budgie not a tiel but it doesn't sound abnormal. Ours knocks things over from a height because he likes you to pick them up for him, strips the wallpaper, chews the cabinets, chews the paint on the window ledge and bites holes in any paper/magazine/book he can find.