Why kill deer? Contraception and conflict in wildlife management

Background/Question/Methods

            When played out on urban and suburban landscapes, deer conflicts do not readily lend themselves to technical solutions.  This is in part because existing technical solutions are weak or challenging to implement in these environments, but also because both the conflicts and possible solutions are grounded in deeper conflicts between value systems.  In thinking about management of deer and other wildlife, it may be helpful to distinguish between material solutions that address overt problems, such as deer-vehicle collisions, and cognitive solutions, which address hidden aspects of community discontent.

             Most discussions of deer conflict management focus around solutions to material problems:  how can we reduce the number of deer-vehicle collisions, prevent damage to ornamental plants, restore forest understory, or control Lyme disease?  There are multiple approaches to mitigation; signage, fencing, creative planting, habitat modification, and appropriate changes in personal behavior all can effectively address material problems.  However, these solutions are often the last to be implemented, if they are implemented at all.  I would argue that mitigation strategies are pursued only reluctantly because they do not address the underlying cognitive conflicts, which rest on questions of how we should feel and think about deer and other wildlife living in our communities.  Where cognitive conflicts are engaged is on the battleground of deer population control:  should we control deer populations, and if so, how?  Public hunting, professional culling, surgical sterilization, reversible contraception, and no action each serve as policy surrogates for strongly-held and mutually antagonistic value systems.

Results/Conclusions

            Injectable immunocontraceptives such as the porcine zona pellucida (PZP) vaccine have been studied in female white-tailed deer for more than two decades.  PZP can be delivered remotely, by dart; has no demonstrated harmful side effects; is safe to give to pregnant animals; does not pass through the food chain; and if administered appropriately can be 90-95% effective.  Deer population stabilization and reduction has been demonstrated using PZP at three field sites, two of which (the National Institute of Standards and Technology, MD, and Fripp Island, SC) I will describe here.  In spite of these successes, political resistance to deer immunocontraception remains stiff, and disproportionate to the (real, but diminishing) material obstacles still facing management application of the technology. This resistance suggests that, although popular among suburbanites, the concept of reversible contraception clashes with value systems held by important management stakeholders, including conservationists.  The values underlying wildlife contraception must be rethought.