Depends on conditions and what kind of birds but you’d need a pretty long lens (like in 300mm-600mm range), decent autofocus and enough image quality to resolve feather detail… it’s pretty tall order for a phone. I hear some people like Moment add-on lenses on their phones but I don’t think they make long telephoto lenses. Most of the long lens add-ons I’ve seen are of really questionable quality…
You’re welcome :) I hope you find a satisfactory solution.