It depends on the baby really. My little Snickers was out of the nest box at about 35 days old (5 weeks) and he was perching from then on. But he was parent reared and he had his parents to watch and learn from. It's different for hand reared babies as they're often a lot more dependent on their human mum and they don't have anyone feathered to learn from. I'm sure Lulu will be perching soon.