I usually call as the situation dictates. Sunday I was talkin to the elk for an hour, I would mew or chirp, sometimes 2-3 times a minute. The herd bull was sure fired up and the cows were going crazy! The bull got most fired up when I would do the cow-in-heat call. Sometimes, I would mew in a tube (to really get the sound out there). I wanted to give the impression that there was more than one cow. They were a couple thousand yards away, but could not get them to come to me. I had a blast though. I love talkin to them, especially when the big boys SCREAM!