The use of box-traps for wild roe deer: behaviour, injuries and recaptures

Abstract

Tracking devices are commonly used to locate and monitor wild animals for studying spatial ecology and survival rates. There is growing interest in capture effects, partially to minimize the impact on the study species, but also for animal welfare reasons. This study aims to examine roe deer behaviour in box-traps, when restrained, when released and during recaptures to quantify injuries and deaths over a period of 41 years. We use data from 2911 captures from 926 individuals between 1973 and 2014. We recorded behaviour inside the box-traps over two seasons. We also recorded behavioural data from 671 catches of 346 individuals during six seasons to study habituation. Additionally, we discuss boxtraps in relation to ethological theory and animal welfare. Over a 41-year period, one roe deer suffering from starvation was found dead in a trap (0.035%), which cannot be solely related to capture (N = 926). About 58% of all roe deer were recaptured at least once during their life time. There was a low prevalence of injuries (0.5% of the captures, N = 2911), and they occurred predominately to the nose or antlers in velvet (in males). During the first hour after capture, animals typically stand very tense between eating bouts. Thereafter, the deer tended to move more softly and exhibited resting behaviours (e.g. lying down). Overall, we conclude that this method of capture and handling had very low impact on the welfare or survival of roe deer, which also habituated to recapture over successive events. • We recorded recaptures, injuries and behaviour during restraint in boxtraps.• About 58% of roe deer were recaptured during their life time.• The estimated direct mortality and wounds was 0.035 and 0.5% respectively.• Roe deer habituate to the capture and become calmer at consecutive captures.Electronic supplementary material The online version of this article

Towards more compassionate wildlife research through the 3Rs principles: moving from invasive to non-invasive methods

“…Refinement (Table 3) includes, for example, the use anesthesia, tranquilization and light-weight radiotransmitters (Harcourt et al 2010, McGuire et al 2014. For minimum injuries and capture of non-target species, it has been recommended to use call playback and taxidermy decoys (Veltheim et al 2015), and to use traps that have been shown to cause no or minimal injuries, for instance, replacing foothold traps with box traps (Kolbe et al 2003, Bergvall et al 2017).…”

Cortisol response of wild ungulates to trauma situations: hunting is not necessarily the worst stressor

“…Abeyesinghe et al 1997, Carragher et al 1997, to specific situations (e.g. DeNicola and Swihart 1997) as live captures in traps (Bergvall et al 2017) or chemical immobilisation (e.g. Sandegren et al 1987, Arnemo 1995, Mentaberre et al 2010.…”

Settle Down! Ranging Behaviour Responses of Roe Deer to Different Capture and Release Methods

“…A novel object, such as the box trap is likely to initially induce fear [ 17 ] and a neophobic stress response (see [ 53 ] for an experimental approach on roe deer). Subsequently, however, when food is offered in proximity to and inside the boxes, habituation and counter conditioning should occur, so that the box will become a positive stimulus associated with food [ 41 ]. Hence, despite the stressful event of capture and release, may still be associated with a reward that encourages the animal to re-visit the area with the box trap independent from their willingness to re-enter the trap.…”

“…We monitored 198 total capture events with two different box trap methods: “box trap (174 captures from seven populations), where the traps were checked several hours after capture (typically in the morning, if traps were set in the evening; [ 40 , 41 ]; “box trap short” (24 captures from two populations), when the traps were checked a maximum of two hours after capture that was notified to operators via remote communication [ 42 ].…”