The number of hunters and wild boar group size drive wild boar control efficacy in driven hunts

Overabundant populations of wild boar (Sus scrofa) are frequent where anthropogenic food is easily available and where hunting is limited. Improving recreational hunting efficacy may contribute to manage these populations. However, we do not know the factors modulating hunting efficacy in a hunting day (i.e., proportion of individuals culled from a population). Additionally, we need to explore which factors drive hunting efficacy in shooting opportunities (i.e., proportion of hunted individuals from a wild boar group in individual shooting opportunities). Here, we analyze the factors explaining wild boar hunting efficacy at the scale of driven hunt and shooting opportunity. Hunting efficacy was surveyed in 92 driven hunts (2017-2018 to 2020-2021 hunting seasons) and in 145 shooting opportunities in Sierra de Gredos (central Spain). We found that hunting efficacy at the scale of the driven hunt was mainly modulated by the number of hunting posts. Indeed, maximum levels of 82 posts showed a fourfold hunting efficacy (59%) compared to minimum levels reaching six hunting posts (16%). At the scale of the shooting opportunity, hunting efficacy was mainly driven by wild boar group size, being negatively related to hunting efficacy: the higher the number of individuals in the group, the lower the shooting efficacy (13-fold; 41% for an individual, 3% for individuals belonging to groups > 7 individuals). Given the need of maintaining native wild boar populations at densities compatible with biodiversity conservation, rural economy, and animal and public health, efforts towards facilitating more hunters per event would improve wild boar hunting efficacy.