Summary
Studies of risk-sensitive foraging have so far focused only on the effect of food demand on choice of feeding site. We suggest that competition is likely to be another factor influencing risksensitivity. A choice experiment with common shrews showed that, in the absence of competition, risk-aversion increased with increasing food intake relative to requirement. When apparent competitors were present, however, shrews were risk-indifferent regardless of their estimated requirement. The switch to risk-indifference in the presence of competitors appears to be an all-or-nothing rule of thumb which is not modified by experience with reward probability distributions.
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Barnard CJ (1984) Snap decisions for survival. New Sci 102 (1411):24–27
Barnard CJ, Brown CAJ (1981) Prey size selection and competition in common shrews (Sorex araneus L.). Behav Ecol Sociobiol 8:239–243
Barnard CJ, Brown CAJ (1985) Risk-sensitive foraging in common shrews (Sorex araneus L.). Behav Ecol Sociobiol 16:161–164
Barnard CJ, Brown CAJ, Gray-Wallis FJ (1983) Time and energy budgeting and competition in the common shrew (Sorex araneus L.). Behav Ecol Sociobiol 13:13–18
Caraco T (1982) Aspects of risk-aversion in foraging white-crowned sparrows. Anim Behav 30:719–727
Caraco T (1983) White-crowned sparrows (Zonotrichia leucophrys): foraging preferences in a patchy environment. Behav Ecol Sociobiol 12:63–69
Caraco T, Chasin M (1984) Foraging preferences: response to reward skew. Anim Behav 32:76–85
Caraco T, Martindale S, Whittam, TS (1980) An experimental demonstration of risk-sensitive foraging preferences. Anim Behav 28:820–830
Krebs JR, Stephens D, Sutherland WJ (1983) Perspectives in optimal foraging. In: Brush D, Clarke J (eds) Perspectives in ornithology. Cambridge University Press, Cambridge, pp 165–221
McNamara J, Houston AI (1982) Short-term behaviour and lifetime fitness. In: McFarland DJ (ed) Functional ontogeny. Pitman, London, pp 60–85
Stephens DW (1981) The logic of risk-sensitive foraging preferences. Anim Behav 29:628–629
Stephens DW, Charnov EL (1982) Optimal foraging: some simple stochastic models. Behav Ecol Sociobiol 10:251–263
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Barnard, C.J., Brown, C.A.J. Competition affects risk-sensitivity in foraging shrews. Behav Ecol Sociobiol 16, 379–382 (1985). https://doi.org/10.1007/BF00295552
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DOI: https://doi.org/10.1007/BF00295552