Turn Costs Change the Value of Animal Search Paths

RP Wilson, IW Griffiths, PA Legg, MI Friswell, O Bidder (Swansea University), LG Halsey (University of Roehampton), SA Lambertucci (CONICET - Universidad Nacional del Comahue, Argentina) & ELC Shepard (Swansea University)

Ecology Letters, Vol. 16, No. 9, September 2013, pp. 1145-1150


The tortuosity of the track taken by an animal searching for food profoundly affects search efficiency, which should be optimized to maximize net energy gain. Models examining this generally describe movement as a series of straight steps interspaced by turns, and implicitly assume no turn costs. We used both empirical- and modelling-based approaches to show that the energetic costs for turns in both terrestrial and aerial locomotion are substantial, which calls into question the value of conventional movement models such as correlated random walk or Levy walk for assessing optimum path types. We show how, because straight-line travel is energetically most efficient, search strategies should favour constrained turn angles, with uninformed foragers continuing in straight lines unless the potential benefits of turning offset the cost.

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This material has been published in the Ecology Letters, Vol. 16, No. 9, September 2013, pp. 1145-1150 the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by Wiley.

Link to paper using doi: 10.1111/ele.12149

Link to paper on the journal website

Ecology Letters