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Prior knowledge about spatial pattern affects patch assessment rather than movement between patches in tactile-feeding mallard

  1. RAYMOND H. G. KLAASSEN1,
  2. BART A. NOLET1,
  3. CASPER H. A. VAN LEEUWEN1,2

Article first published online: 20 DEC 2006

DOI: 10.1111/j.1365-2656.2006.01184.x

Issue

Journal of Animal Ecology

Journal of Animal Ecology

Volume 76, Issue 1, pages 20–29, January 2007

Additional Information

How to Cite

KLAASSEN, R. H. G., NOLET, B. A. and VAN LEEUWEN, C. H. A. (2007), Prior knowledge about spatial pattern affects patch assessment rather than movement between patches in tactile-feeding mallard. Journal of Animal Ecology, 76: 20–29. doi: 10.1111/j.1365-2656.2006.01184.x

Author Information

  1. 1

    Department of Plant–Animal Interactions, Netherlands Institute of Ecology, Royal Netherlands Academy of Arts and Sciences (NIOO-KNAW), PO Box 1299, NL-3600 BG Maarssen, the Netherlands;

  2. 2

    Landscape Ecology group, Department of Biology, Utrecht University, PO Box 800·84, NL-3508 TB, the Netherlands

* R.H.G. Klaassen, Department of Plant–Animal Interactions, Netherlands Institute of Ecology, Royal Netherlands Academy of Arts and Sciences (NIOO-KNAW), PO Box 1299, NL-3600 BG Maarssen, the Netherlands. E-mail: r.klaassen@nioo.knaw.nl

Publication History

  1. Issue published online: 20 DEC 2006
  2. Article first published online: 20 DEC 2006
  3. Received 27 April 2006; accepted 21 September 2006

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Keywords:

  • incomplete information;
  • learning;
  • marginal value theorem;
  • optimal foraging theory;
  • spatial arrangement

Summary

  • 1
    Heterogeneity in food abundance allows a forager to concentrate foraging effort in patches that are rich in food. This might be problematic when food is cryptic, as the content of patches is unknown prior to foraging. In such case knowledge about the spatial pattern in the distribution of food might be beneficial as this enables a forager to estimate the content of surrounding patches. A forager can benefit from this pre-harvest information about the food distribution by regulating time in patches and/or movement between patches.
  • 2
    We conducted an experiment with mallard Anas platyrhynchos foraging in environments with random, regular, and clumped spatial configurations of full and empty patches. An assessment model was used to predict the time in patches for different spatial distributions, in which a mallard is predicted to remain in a patch until its potential intake rate drops to the average intake rate that can be achieved in the environment. A movement model was used to predict lengths of interpatch movements for different spatial distributions, in which a mallard is predicted to travel to the patch where it expects the highest intake rate.
  • 3
    Consistent with predictions, in the clumped distribution mallard spent less time in an empty patch when the previously visited neighbouring patch had been empty than when it had been full. This effect was not observed for the random distribution. This shows that mallard use pre-harvest information on spatial pattern to improve patch assessment. Patch assessment could not be evaluated for the regular distribution.
  • 4
    Movements that started in an empty patch were longer than movements that started in a full patch. Contrary to model predictions this effect was observed for all spatial distributions, rather than for the clumped distribution only. In this experiment mallard did not regulate movement in relation to pattern.
  • 5
    An explanation for the result that pre-harvest information on spatial pattern affected patch assessment rather than movement is that mallard move to the nearest patch where the expected intake rate is higher than the critical value, rather than to the patch where the highest intake rate is expected.
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