Effectiveness of solar blinkers as a means of crop protection from wild boar damage

The population density of wild boar (Sus scrofa) in Northern Switzerland has increased dramatically during the last three decades and the species has become a major threat to agriculture, causing severe damage to crops and grassland. Vulnerable fields have to be protected from wild boar incursion, which is in most cases achieved by using electric fences. Alternatively, deterrents basing on optical, acoustical or gustative effect are available. The effectiveness of most of these systems has not previously been scientifically tested in the field. In our study we investigated the effectiveness of solar blinkers at baited luring sites. We conducted field experiments at 4 different sites with free-ranging wild boars from January 2007 to January 2008. Data from 504 inspections of the luring sites indicate that solar blinkers reduced the probability of wild boar visits at the luring sites by 8.1% compared to the control sites. We therefore evaluate deterrence effect of solar blinkers to be insufficient for effective crop protection. Probability of wild boar visits at the luring sites changed throughout the study period, showing seasonal variation of the extent of wild boar activity in the fields.