Efficacy and Cost of GonaCon™ for Population Control in a Free‐ranging White‐tailed Deer Population

Abstract

As white‐tailed deer populations increase in developed and urban areas, lethal management is necessary to control population growth. However, concerns about safety and negative attitudes towards lethal control and using firearms near houses have prompted many communities to pursue nonlethal techniques. Therefore, in 2014 we initiated a 5‐year project to attempt to stabilize the local deer population on Bald Head Island (BHI), North Carolina, using the immunocontraceptive GonaCon™. Since 2014 we captured and inoculated 77 female deer with GonaCon™. From 2017 to 2018 we evaluated the efficacy and cost of GonaCon™ at reducing pregnancy in adult female white‐tailed deer on BHI. We obtained blood samples from 49 deer that had received either 1 or 2 doses of GonaCon™, and from 19 female deer that had received no GonaCon™ for pregnancy analysis using the pregnancy specific protein B assay. All untreated deer sampled were pregnant (n = 19), whereas 67% of deer sampled that received only a single dose were pregnant (n = 27), and 14% of deer that received 2 doses (n = 22) were pregnant. Thus, 2 doses of GonaCon™ were necessary to reduce pregnancy rates below 50%. The total direct cost of the 5‐year immunocontraception project was $320,030.52 and averaged $2,078.12/capture with an overall efficacy of 33% for one dose and 86% for 2 doses of GonaCon™. Conversely, the estimated cost for the local government (i.e., Village of Bald Head Island) to cull 30 deer in 2018 was $16,163.63, or $538.79/deer. The estimated deer population was 113 in 2014 and increased to 198 individuals by 2018. Further population projections suggested the white‐tailed deer population is projected to reach 342 individuals by 2022. Although 2 doses of GonaCon™ were effective at reducing pregnancy, administration across the BHI deer population was not successful in reducing the deer population, and culling will likely be necessary to reduce the population. © 2021 The Wildlife Society.

Experimental oral delivery of the systemic acaricide moxidectin to free-ranging white-tailed deer (Artiodactyla: Cervidae) parasitized byAmblyomma americanum(Ixodida: Ixodidae)

“…Other nontraditional means of white-tailed deer management exist such as sharpshooting (DeNicola et al 1997), sterilization (Boulanger et al 2012, DeNicola and DeNicola 2021), and immunocontraception (Walker et al 2021), but are often cost prohibitive for use in a town or county-wide basis. In part due to the challenges and limitations of deer management alone for tick abatement, alternative host-targeted strategies have been proposed, specifically the use of 4-poster devices (C. R. Daniels, Inc., Ellicott City, MD; Pound et al 2000, Schulze et al 2009, Williams et al 2021), which use corn to entice animals to self-apply a topical formulation of permethrin to their pelage.…”