surely calls are used more to get a animal in range to be shot, rather than trapped , as for the new technology "whats wrong with blowing a piece of grass between your thumbs " it works for those who know how to do it properly, another piece of modern technology that was shown to me in the 1950s at Kimboulton was a device that was fitted to kiddies dolls , the ones that said mam-ma when tilted, the man demonstrating it was Keith Godby and he called eight Hares and a fox into shotgun range in what seemed like minutes, as I have said before "all the kit is out there ,you just have to know