Let it be, I've got birds nesting in my roof lining and I don't give a damn. Its almost lovely to wake up to the sound of little birds in the morning. Though these are little finches and the like, nothing big like crows or pigeons.
We actually had some pigeons living in the roof a while back. When I got around to removing them I found the entire attic full of dead pigeons. Not fun.
Eh it left after a few weeks. Coulda let my dog chase off the pigeon and eat the chick but I'm like... way to nice for that. Oh and its a balcony not a porch. Escuse mi inglis.