In Germany approximately 250.000 Wildlife-Vehicle Collisions (WVC’s) with large terrestrial mammals, especially roe deer (Capreolus capreolus) and wild boar (Sus scrofa), are reported every year. However, the reaction of terrestrial mammals towards oncoming vehicles has only scarcely been studied, yet (e.g. Waring et al 1991, D’Angelo et al. 2006, Blackwell and Seamans 2009, Lima et al. 2014). One reason might be that obtaining sufficient data along roads is limited due to laws governing personal data protection. Therefore, we used thermal network cameras to record wildlife’s behavior near roads.
We selected 9 testing sites at primary, secondary and tertiary roads with reported hotspots in WVC’s. Each testing site had forest on one side and field on the other site. We recorded three testing sites at the same time for 8 weeks using one thermal network camera for each site (Axis Q1931-E with a 10.7 ° lens, Axis Communications AB, Inc., Lund, Sweden). The study was conducted between August 2015 and January 2016 from dawn till dusk. The frequency of sightings and time spent near roads for each species was analysed. Furthermore, animal’s reactions was categorised into four categories: 1) flight, 2) alarm, 3) movement and 4) no reaction (see Ujvari et al 1998).
Between 8 and 60 sightings per night and testing site were recorded. Most abundant were deer (37,5 %), followed by rabbits (29 %), red foxes (23 %), badger (6 %) and wild boar (4 %). Badger and red foxes spent the longest time near roads (160 secs and 154 secs) per sighting. Deer spent on average 130 secs, wild boar 72 secs and rabbits 63 secs near roads. No species showed any significant reaction or change in behavior towards oncoming vehicles.
Our results show that deer are the most abundant large mammals near roads, which is not surprising due to their estimated high population density. Though, in areas with roe deer, red deer and fallow deer the species’ differentiation between females was not always possible due to difficulties in size estimation. Furthermore, the relatively long duration of stay of red foxes and badgers near roads might indicate a higher risk in WVCs. However, due to their small body size collisions with these species might be underreported. Nevertheless, the lack of reaction towards oncoming vehicles might show a habituation to traffic and missing risk estimation of approaching vehicles.
wildlife vehicle collisions; behavior at roads; thermal camera images