mudhen,
I recall reading a summary of several studies, which concluded that at least 1/3 of the population of coyotes in a large area would have to be killed not just one year, but every year for several years, to significantly reduce coyote predation. This wasn't just because of increased reproduction, but if 1/3 were taken in a relatively small area, coyotes from surrounding areas would quickly move in. Have you seen any of that research?
MD, I don't keep up with the literature like I used to do before I retired, and a quick google search didn't turn up that particular study. However, I did run across a summary paper by Fred Bryant at Texas A&M that, among other things, concluded that:
Considering the strong compensatory reproductive response of coyote populations to reduction, if control, sport, and bounty hunting collectively do not reduce numbers annually on a continuing basis by at least 75 percent, no sustained decline in the population can be achieved. Therefore, to summarize, in most situations, killing coyotes at rates below 75 percent may merely stimulate reproduction and aggravate the problem by increasing the seasonal population pressure on the food supply. Sport calling, opportunistic shooting and legal fur trapping do not significantly impact numbers of individuals in most coyote populations, nor do they reduce predation on game and nongame species to any significant degree. However, control efforts that target and remove problem animals can be very effective at mitigating or eliminating predation on domestic animals.
