Hurly TA, Oseen MD
Department of Biological Sciences, University of Lethbridge
Anim Behav. 1999 Jul;58(1):59-66. doi: 10.1006/anbe.1999.1130.
We tested the risk-sensitive foraging preferences of wild rufous hummingbirds, Selasphorus rufus, with three types of artificial flowers. All three flower types provided the same mean volume of 30 µl of sucrose, but differed in terms of variability of the reward: constant, low variance and high variance. In trinary comparisons, subjects preferred the low-variance reward over the constant reward, and the constant reward over the high-variance reward; a result not predicted by risk-sensitive foraging theory. However, when tested with traditional binary comparisons, hummingbirds showed conventional risk-averse behaviour and selected the constant reward over the low- or high-variance rewards. This reversal of preference represents a context-dependent foraging preference. The utility of selecting intermediate levels of risk and the source of the preference reversal are discussed relative to risk-sensitive foraging theory and the effects of local context on foraging choices. Copyright 1999 The Association for the Study of Animal Behaviour.
我们用三种人造花测试了野生棕煌蜂鸟（Selasphorus rufus）对风险敏感的觅食偏好。所有三种花提供的蔗糖平均量均为30微升，但奖励的变异性不同：恒定、低方差和高方差。在三元比较中，实验对象更喜欢低方差奖励而非恒定奖励，更喜欢恒定奖励而非高方差奖励；这一结果并非风险敏感觅食理论所预测的。然而，当用传统二元比较进行测试时，蜂鸟表现出传统的风险规避行为，选择恒定奖励而非低方差或高方差奖励。这种偏好逆转代表了一种依赖情境的觅食偏好。相对于风险敏感觅食理论以及局部情境对觅食选择的影响，我们讨论了选择中等风险水平的效用以及偏好逆转的根源。版权所有1999动物行为研究协会。
