cachedistance data dryadData were collected in the field and entered into SPSS. Column headings are: SquirrelID=individual squirrels, obsnum = observation number for each individual squirrel, site=which of 4 sites the data were collected from, cachedistance=distance of the cache, in metres, from the nearest tree, numsqpres=the number of other squirrels present at the time the focal squirrel made the cache, disturbances=the number of people that passed through the site during the observation periodforagedistance data dryadData were collected in the field and entered into SPSS. Column headings are: SquirrelID=individual squirrels, obsnum = observation number for each individual squirrel, site=which of 4 sites the data were collected from, cachedistance=distance of the cache, in metres, from the nearest tree, numsqpres=the number of other squirrels present at the time the focal squirrel made the cache, disturbances=the number of people that passed through the site during the observation periodhuman predation data dryadData were collected in the field and entered into SPSS. Data columns are as follows: location=site where squirrel was observed, Squirrel_ID=individual squirrel ID, V3=observation number for each squirrel, date=date of observation, time=time of day observation was taken, No_of_human=number of humans present when the squirrel was observed, No_of_dog=number of dogs present when the squirrel was observed, distancem=distance in metres between the squirrel and the nearest human and/or dog, escaped_or_not=whether or not the squirrel stopped it's current activity and ran, escaped=whether or not the squirrel stopped it's current activity and ran using 0 for no and 1 for yesartificial cache datadata were collected in the field and entered into an Excel file. Column definitions are within the file itself.

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.