Data from: Behavioral flexibility vs. rules of thumb: how do grey squirrels deal with conflicting risks?

In order to test how flexibly animals are able to behave when making trade-offs that involve assessing constantly changing risks, we examined whether wild Eastern grey squirrels showed flexibility of behavioral responses in the face of variation in two conflicting risks, cache pilferage and predation. We established that cache pilferage risk decreased with distance from cover, and was thus negatively correlated with long-term predation risk. We then measured changes in foraging and food caching behavior in the face of changes in the risk of predation and food theft over a short time-scale. We found that, overall, squirrels move further away from the safety of cover when they cache, compared to when they forage, as predicted by pilferage risk. However, there was no effect of immediate pilferage or predation risk (i.e. the presence of potential predators or pilferers) on the distance from cover at which they cached, and only a slight increase in forage distance when predation risk increased. These results suggest that ‘rules of thumb’ based on static cues may be more cost-effective for assessing risk than closely tracking changes over time in the way suggested by a number of models of risk assessment.

为探究动物在开展涉及评估持续动态变化风险的权衡决策时，可通过何等灵活性调整自身行为，我们针对野生东部灰松鼠展开实验，以验证其在面对两种冲突风险——缓存盗食（cache pilferage）与捕食风险——的变化时，是否表现出行为响应的灵活性。我们证实，缓存盗食风险会随与遮蔽物的距离增加而降低，因此与长期捕食风险呈负相关。随后，我们在短时间尺度内，测量了捕食风险与食物盗食风险发生变化时，松鼠的觅食与食物缓存行为变化情况。整体而言，研究结果显示：与觅食阶段相比，松鼠在缓存食物时会进一步远离遮蔽物的安全区域，这与缓存盗食风险的理论预测相符。不过，即时盗食风险或捕食风险（即潜在捕食者或盗食者的存在）并未对松鼠的缓存距离产生显著影响；仅当捕食风险升高时，松鼠的觅食距离才出现小幅增加。上述结果表明，相较于诸多风险评估模型所提出的实时追踪随时间变化的风险的路径，基于静态线索的“经验法则”在风险评估中或许具备更高的成本效益。