From my time volunteering at a zoo, I was told that it used to be common practice to pinion (surgically remove part of one wing) most open area birds, but that in more recent times it's only done for large groups of outdoor animals, like flamingos, because there are just too many animals to check on every single time they molt their feathers. Nowadays for animals like storks or cranes, they'll trim the feathers when the new ones are done growing in so the animal cannot fly away. The pelicans kept in outdoors in my old zoo were all rescues and could not fly anyway.