This guy is dead on!!
We broke down a predator pit here for game birds(pheasant, turkey) by hammering the fox, coons, skunks, feral housecats. The project is ongoing and has been in place for 5 years now. The hen to rooster ratio is finally becomming significant enough that the project could be stopped and we would still have 5 star bird hunting. The same can be said for our deer population and coyotes. The yotes have been hammered good and the fawn recruitment has increased dramatically for several herds that were BELOW objective until we took intensive predator(say coyote) actions. Those herds now sport SURPLUS animals that offer an early season on doe/fawn; a GOOD way to get kids into hunting. We had 600 special doe/fawn tags available just this year.
I've worked with the 'predator pit' scenario and this professor has got it right!! IF the population is low and the predator population is high the game birds/animals CANNOT recover enough to have healthy, sustainable populations.
Another factor that can create 'predator pits' is a couple of years of bad weather and desease with NO predator control.
When we started our SMALL predator control project? There were so many coons roaming my yard looking for food trhat they attack and eat each other. To many is no good, some is ideal.
Currently we are studying the effects of predation on sage grouse populations and the facts support predator control to get those birds out of the 'predator pit' that they are currently in.