Personally I don't care for rats. Have heard domesticated ones can have nice personalities, but what kind of damage I have seen them do to a home and to humans, I don't like them.
That said. It seems they, as part of the food chain will help clean up the sick, dead and dying and weak birds (although I realize eggs as well).
Won't mass amounts of bird poop just cause ammonia and nitrates, too much algae, mess up tide pool areas, etc? I would think that, but the report doesn't seem to indicate it as a concern. Maybe it proves rats are worse than _____ (lots of stuff) ?!?!