Wild pets for the city :) .
- choose a bright spot to plant your flowers/foodplants. Butterflies love sun!
- plant them in an area that does not experience mosquito fogging
- rear some in a container if you are worried that they might be eaten by birds, but make sure you change the leaves and clean their poo out every day -- for big caterpillars especially!
- use pesticides, herbicides or any other chemicals
- disturb the caterpillars when they are pupating or in pupal stage