Behavioral flexibility versus rules of thumb: how do grey squirrels deal with conflicting risks?

Abstract

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 2 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.