I have been thinking about that myself, I am wondering if I run my distress calls a little to long and they know something is up. My daughter has small lungs and her distress calls are real short kinda like a small lunged rabbit. I dont know really but my son and I went out today( didnt call in a damn thing, daughter was in dance class) but i noticed when he called the distress cry was a lot longer than the one my daughter does, that made me think, rabbits small lungs, daughter small lungs. Each of her cries last about .5 seconds while my son and mine were about 1 to 1.5 seconds. I am going to tape her calling and go out by myself and see if it works. I am looking at getting the foxpro
it seems to have good reviews.