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Predicting the strength of interference more quickly using behaviour-based models

Authors

  • Richard A. Stillman,

    Corresponding author
    1. Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK;
      Richard Stillman, Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK. Tel: 01305 213570. E-mail: rast@ceh.ac.uk
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  • Alison E. Poole,

    1. Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK;
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  • John D. Goss-Custard,

    1. Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK;
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  • Richard W. G. Caldow,

    1. Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK;
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  • Michael G. Yates,

    1. Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK;
    2. Centre for Ecology and Hydrology Monks Wood, Abbots Ripton, Huntingdon, PE17 2LS, UK; and
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  • Patrick Triplet

    1. Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK;
    2. RN Baie de Somme, SMACOPI, 1 Place Amiral Courbet, F-80100 Abbeville, France
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Richard Stillman, Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK. Tel: 01305 213570. E-mail: rast@ceh.ac.uk

Summary

  • 1 Interference between foraging animals can be quantified directly only through intensive studies. A quicker alternative is to predict the strength of interference using behaviour-based models. We describe a field method to parameterize an interference model for shorebirds, Charadrii.
  • 2 Kleptoparasitic attack distance is the main factor affecting the strength of interference but has rarely been measured. Attack distance is related to handling time, a frequently measured parameter, allowing the model to be parameterized for systems in which attack distance has not been measured.
  • 3 The model accurately predicts the strength of interference between oystercatchers Haematopus ostralegus L. feeding on cockles Cerastoderma edule L. and the absence of interference between bar-tailed godwits Limosa lapponica L. feeding on lugworms Arenicola marina L. at low competitor densities.
  • 4 We predict the strength of interference in black-tailed godwit Limosa limosa L. and oystercatcher systems in which it has not been measured previously. The strength of interference is almost entirely determined by attack distance; interference is stronger in systems with longer attacks. Interference is usually weaker in black-tailed godwits because handling time is generally shorter and this limits attack distance.
  • 5 The interference model can be parameterized much more quickly than the alternative of measuring interference directly. Behaviour-based models have the potential to be a valuable tool for predicting the strength of interference.

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