We use howlers a lot in KS. to roost birds and it works often times. I can remember one evening that we were trying to locate some roosted birds with our howlers and we couldn't get any thing to talk to the howls. My buddy jumped in the truck to leave and when he slammed his door, I heard them gobble. I was like, "did you hear that, do it again." So he opened his door and slammed it shut again, and once again they gobbled. SO now, if all else fails, we slam adoor on the vehicle.