Thanks! At various times I've used willow, runner beans, buddleia and bamboo in their aviaries. They haven't really done much damage to any of it, apart from some harmless nibbling, as they seem to prefer stripping bark off their perches (which I replace regularly). They do like eating the beans, off the vines, but they won't touch them if served in a bowl! Generally speaking they haven't rummaged about in the pots at all, so it's not been necessary to put gravel on top of the soil, but I should probably do this as a precaution anyway. It's definitely worth putting plants in your flights as it makes them so much more attractive for all concerned. The trick of course it to position the plants carefully so they don't get droppings on them or obstruct the birds' flight. What parrots have you got?