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

Abstract

The fitting of tracking devices to wild animals requires capture and handling which causes stress and can potentially cause injury, behavioural modifications that can affect animal welfare and the output of research. We evaluated post capture and release ranging behaviour responses of roe deer (Capreolus capreolus) for five different capture methods. We analysed the distance from the centre of gravity and between successive locations, using data from 14 different study sites within the EURODEER collaborative project. Independently of the capture method, we observed a shorter distance between successive locations and contextual shift away from the home range centre of gravity after the capture and release event. However, individuals converged towards the average behaviour within a relatively short space of time (between 10 days and one month). If researchers investigate questions based on the distance between successive locations of the home range, we recommend (1) initial investigation to establish when the animals start to behave normally again or (2) not using the first two to three weeks of data for their analysis. We also encourage researchers to continually adapt methods to minimize stress and prioritize animal welfare wherever possible, according to the Refinement of the Three R’s.

Evaluating expert‐based habitat suitability information of terrestrial mammals with GPS‐tracking data

“…We obtained habitat data from a global map of terrestrial IUCN habitat types in 2015 at a ~ 100-m resolution (Jung et al, 2020). For each individual, we removed locations from the first 7 days of tracking after capture (on average 3.9% of the data), to avoid possible effects of capture and handling on the individual's locations (Bergvall et al, 2021;Gese et al, 2019;Mayer et al, 2019;Morellet et al, 2009). Furthermore, we removed locations that could be considered outliers based on unrealistic distances or speed between successive locations (on average 0.5% of the data, see Supporting Information Appendix S5 for a detailed description of the data cleaning).…”

Sensitivities of mammals to capture and tagging: faster recovery in human-disturbed landscapes

“…The effects of physical capture, chemical immobilization, and restraint of animals on possible post-release behavioral modifications are, however, understudied in wildlife species, which may affect the welfare of animals and the interpretation of study results (but see: [47,52,11]). The capture and handling process involves several stress-inducing and physically demanding events that are attributable to human presence and may involve sudden or loud noises, social isolation, limited movement, and impaired vision [69,25,8]. The use of neurologically active chemicals can affect animal behavior and movement for several days [33,14], ultimately triggering behavioral changes [2,28,60].…”

“…The effects of capture (e.g., helicopter darting or capture, chasing, trapping) on animal behavior can vary widely across species, sex, tag size and type, deployment duration, the specific deployment procedure, or the environment [29,59,78,47]. Species differ in stress responses, especially throughout the initial days of tracking, and the time taken to return to their normal behavior [10,8]. Notably, animals living in anthropogenic landscapes adapt their space use and become more tolerant to human disturbances [22,55].…”