The only way to keep them from being flighty is to be around them a lot. The amount of time you spend with them isn't enough for them to become tame. If you are the one feeding and watering them every day, though, they should stop freaking out when you're near. Mine don't want me to touch...
When you scoop them up, try to come at them from the sides rather than from above. They will be less afraid of that approach. Swooping in from above feels too much like a hawk/predator to them, I think.