We study foraging decisions in wild fox squirrels (Sciurus niger; introduced to California in the early 20th Century). We study the decisions in both the solo forager and squirrels making decisions in competitive social contexts. Scatter hoarding tree squirrels (e.g., Eastern Gray Squirrel, Fox Squirrel, Southern Flying Squirrel) make thousands of foraging decisions – should I eat or cache this nut? – during the critical fall harvest of acorns and other tree seeds. Such seeds are hidden individually yet squirrels cannot defend the areas where they are hidden. Instead, they rely on careful economic decisions on which nuts to hide and where to hide them, as well as spatial memory for cache locations. Finally, they also steal caches made by other squirrels, which is an area of our current interest. We study these questions year-round using computational models of behavior as well as experimental and observational studies of a small population of individually-marked, habituated fox squirrels on the Berkeley campus.