Exactly! It's very difficult for some people to grasp this concept but it's true. Trapping is a continual process also. It's not a one time effort if a person truly wants to control a coyote population.You will never truly thin a population by calling. I trapped a farm that had all experience levels of calling done(including myself) on it for a couple months and about 6 were killed. I set 18 traps and caught 24 in three weeks.