I.

There is increasing demand for benign approaches to the resolution of conflicts between human interests and wildlife. One non-lethal method to reduce the growth and expansion of overabundant wildlife populations is fertility control. Significant progress has been made in recent years on the development of fertility control agents, culminating in the availability of single-dose injectable immunocontraceptive vaccines that inhibit the fertility of individuals for several years. The potential application of such technology is explored here using the European rabbit, gray squirrel, wild boar, and European badger as examples of species that pose problems of damage to agricultural and forestry interests, disease transmission and threats to biodiversity. A simple model is developed that predicts the likely general population consequences of varying levels of infertility for species with differing demographic characteristics. This suggests that low levels of fertility control will have little impact on population size in species with high reproductive rates and high population turnover rates. Modest levels of infertility can significantly reduce the populations of species with relatively low intrinsic rates of increase. However, these reductions may take longer than those arising from high levels of imposed infertility in species with rapid population turnover rates. The modeling approach, as outlined here, could be used to inform future field studies by identifying suitable target species and making predictions about population responses that can be tested empirically. These studies will be necessary to realize the potential of the emerging fertility control technologies in the form of practical wildlife management applications.