Comparative evaluation of infrared thermography and spotlight counts for European hare surveys in farmland habitats

The European hare is still a common species in agricultural environments, although it has shown a significant decline in many European countries compared to a few decades ago. Monitoring this species, conducted for wildlife management or research purposes, is carried out using various methods, with spotlight counts being the most prevalent. Although infrared thermography is more expensive, its use in wildlife monitoring is becoming increasingly common. We compared the two methods for monitoring the European hare in 20 sample areas in central Italy. Infrared thermography detected 37% more hares compared to spotlight counts. This difference is partly due to the greater distance at which hares can be detected with thermography but partially because this tool allows for better detection of hares in environments where the vegetation is taller, such as forage legumes and fallow fields. Overall, the densities estimated by distance sampling on the observations collected with the two methods were not significantly different. However, in the hilly environments typical of central Italy, infrared thermography may be more accurate and reduce the risk of underestimation.