Anywhere from 15-20 seconds to a couple minutes works for me and wait maybe 2 to 6 minutes between. Unless you can see everything around you starting quite is indeed a good idea. I' ve never been calling at night so I can' t say about that. Remember you' re trying to mimic a hurt animal, not a digitally programmed machine that sets even intervals, vary it up, keep the coyotes guessing, and whatever you do, call with PASSION! Feel the pain![:-]