Stick or twist: roe deer adjust their flight behaviour to the perceived trade-off between risk and reward. (February 2017)

• Record Type: Journal Article
• Authors: Bonnot, Nadège C.; Hewison, A.J. Mark; Morellet, Nicolas; Gaillard, Jean-Michel; Debeffe, Lucie; Couriot, Ophélie; Cargnelutti, Bruno; Chaval, Yannick; Lourtet, Bruno; Kjellander, Petter; Vanpé, Cécile
• Is Part Of: Animal behaviour. Volume 124(2017)
• Page Start: 35
• Page End: 46
• Publication Date: 2017-02
• Subjects: assessment interval -- deer -- detection delay -- flight initiation distance -- flush early and avoid the rush hypothesis -- optimal escape theory -- risk assessment -- risk–resource trade-off -- starting distance -- threat monitoring; Animal behavior -- Periodicals; 591.5
• DOI: 10.1016/j.anbehav.2016.11.031
• Languages: English
• ISSNs: 0003-3472

Abstract

Abstract : Because avoiding predation is crucial for fitness, foraging animals must trade acquisition of high-quality resources against risk avoidance when the best resources occur in locations with high predation risk. Although optimality models predict the distance at which an animal should initiate vigilance and flight, many studies have shown that animals generally flee soon after detecting an approaching threat, supporting the 'flush early and avoid the risk' (FEAR) hypothesis. Despite this, flight behaviour varies markedly depending on context, suggesting some behavioural plasticity in the response of prey to a given threat. We evaluated the degree of plasticity in the flight responses of roe deer, Capreolus capreolus, a highly flexible species which thrives in human-dominated landscapes. Based on individually identifiable animals and a standardized flight initiation protocol, we measured the distance at which a deer detected an approaching threat, and the distance at which it subsequently initiated flight. Our results provide strong support for the FEAR hypothesis, suggesting that alert and flight responses are strongly coupled in roe deer. However, the perceived level of both risk (in terms of landscape openness and proximity to human infrastructure) and reward (in terms of habitat quality) influenced the time it took for a deer to detect an approaching threat, and the subsequent time for which the threat was tolerated prior to flight. Overall, our findings indicate that although roe deer minimize monitoring costs when assessing risk by fleeing early, they also adjust their monitoring and flight responses to the local risk–resource trade-off. Highlights: Flight behaviour in response to a human indexes tolerance to perceived predation risk. We measured the detection delay and assessment interval of roe deer across contexts. Landscape structure and habitat quality influenced detection and tolerance of threat. Detection and tolerance of threat by roe deer varied with the risk-reward trade-off. Alert and flight responses are highly correlated, supporting the FEAR hypothesis.