Predators only eat the quail they can catch. If you have good quail habitat, the quail will survive the predators. And their are many other predators that are as much, if not more, of a threat to quail than coyotes and bobcats. Here, coons, skunks, and birds of prey all make a lot bigger dent in the quail population than the few bobcats we have. Coyotes aren't a major predator, either.