Evaluation of a combined and portable light-ultrasound device with which to deter red deer

Human–wildlife conflicts are a growing problem in Northern Hemisphere where wild ungulates are one of the taxonomic groups most frequently involved. To mitigate these conflicts, it is essential to develop preventive actions able to avoid encounters between wildlife and human (activities). We here employed photo-trapping to evaluate the behaviour of red deer ( Cervus elaphus ) when confronted with dissuasive portable deterrents that function on the basis of changing patterns of light and ultrasound. This was done by following a before/after experimental design, with two phases: (i) a test phase, with active deterrents, and (ii) a control phase, without deterrents. When deterrents were activated they achieved a 48.96% reduction in the frequency of use by red deer (up to 66.64% when it was assessed on a thinner Sect. 10 m wide from the line of deterrents) and produced a reduction of 67.71% in the frequency of deterrent-line crossings. However, a habituation effect was detected since the use by red deer of the treatment area increased as time since treatment. These results indicate that these portable devices are effective as regards dissuading deer, mainly on short time scales. The deterrents tested here could be suitable for use at focal points for short periods or in combination with other methods to improve their effectiveness in vulnerability points. This device could potentially be used to mitigate conflicts caused by wildlife species and in response to relevant and timely situations, such as vehicle collisions and damage to crops, among others.