Savannah was taking card of rescued sheep, so of course she was the first person you'd think of to take in an injured magpie. Animal lovers are animal lovers, after all. Ziggy bonded with her humans, even after she was allowed outside, and after several months she struck out on her own.
With human children, we raise them and equip them the best we can so that they can navigate the world on their own, but we also expect to keep communicating with them after they do. That's not always possible with wild animals. We bond with pets and take care of them for a lifetime. Although we can bond with any animal we take care of, wildlife is different. It's always best if they can get along in their natural habitat, yet it can be heartbreaking. All Savannah can do is be glad that she helped an animal in need, and hope that Ziggy is living her best life out there somewhere.