Snake prevention
Roadrunners and king snakes go a long way to preventing rattlesnakes from setting up shop. Both like to dine on rattlers. The kings will also eat everything else a rattler would (mice, rats, etc). So you get all the benefits offered by having snakes around without the risk of having a venomous snake.
My mother grew up in an area with no shortage of either wildlife or humans. Her father had to kill several rattlesnakes in the yard or garden every year until one year a nice big king snake moved into the yard. Grandma saw another snake, didn't know one from another, and called him to come take care of yet another "rattler." He showed up, recognized the difference right away, and promptly instructed grandma and all the kids that the new snake was not to be disturbed for any reason. It took to sunny itself on the rock steps leading to the back porch which prompted grandma and her girls to walk the long way around--from the front door--to hand laundry out to dry. But it never tried to bite anyone, wouldn't have been a real issue even if it had, and they never saw another rattler in the yard again.
Years later, my mother endured my adolescent fascination with snakes as I kept a California King as a pet for a summer and then turned it loose in the yard.
Not that I want to bet real money on who wins a fight between a King and one of those 9 foot monster rattlers y'all are photographing. WOW. The stuff of nightmares there.
Charles