This very short video shows why it's important to move the new green box slowly, one step at a time. After moving it about 1/2 meter downwards, quite a few of the foraging bees have started to try and get back into the original white box. Fortunately, I knew they would probably try to do this and had the door closed. When all the bees have got accustomed to the new green box position, it can be moved down another couple of ladder rungs.