Foreword to the Special Issue on 'Fertility control for wildlife in the 21st century'

The economic and environmental impacts of wildlife are increasing in parallel with renewed public interest in non-lethal methods, such as fertility control, to manage these impacts. The Wildlife Research 2008 Special Issue on Fertility Control for Wildlife (Vol. 35) published following the 6th International Conference on Fertility Control for Wildlife held in 2007 in York, United Kingdom, reported studies on the effects of contraceptives on individual animals and populations, with most papers focusing on ungulates. In the past 15 years, significant progress has been made in developing novel contraceptives for wildlife and in designing methods to deliver these agents. Concurrently, the general debate on wildlife management has widened to include public attitudes and perceptions of novel and traditional methods, animal welfare issues, costs, feasibility, and regulatory and ethical issues. These developments have broadened our understanding of contexts and species for which fertility control could be employed, either as a stand-alone method or to complement other population management options. These topics were reflected in the presentations given at the 9th International Conference on Wildlife Fertility Control, held in Colorado Springs (USA) in 2022. Here, we introduce a special issue featuring selected presentations from the 2022 conference. These studies showcase the wide spectrum of topics that covered novel contraceptives tested on several species, ranging from mice to elephants. They also illustrate new methods to deliver contraceptives, models on the impact of fertility control on populations, feasibility, cost of practical applications of fertility control, discussions on animal welfare and human dimension of these approaches.