Nature of bird injury mostly depends on how the bird is exposed - full on strike, or did he just get "winged?"
Maybe with large migratory populations, the carnage will continue for a long time. The elevated track people mover in Miami didn't run for a year or so after the tracks were built - pigeons thought the tracks were just the greatest place ever made to hang out, nest, etc. The first months of operation (of the very quiet electric cars) were a nasty pigeon bloodbath, feathers and guts everywhere. After a few months, the remaining pigeons caught on, there's hardly ever one run over anymore. I don't think any special mitigations (tiny cow-catchers, warning lights, sounds) were put in place, just Darwin in action.