Keep it in Your Pants, Mother Nature
In past decades, particularly the 1970s and 80s, especially fecund populations of wildlife such as Canadian Geese and Whitetail Deer were practically extinct, thanks to over-harvesting on the part of hunters all across the North American continent, DDT poisoning and natural ebbs of the population cycle. Now, partly in thanks to shorter hunting seasons and conservation efforts especially designed to promote these once-threatened species, herds and flocks have become over-eating, over-breeding menaces. Often times these animals are in and around human populations, which makes them difficult or illegal to hunt, and new methods of population control are being investigated.
New drugs, and old drugs with new uses, are becoming available to control these populations. Birth control is no longer just for promiscuous teenagers any more!